Skip directly to search Skip directly to A to Z list Skip directly to site content




The Agency for Toxic Substances and Disease Registry (ATSDR) is part of the U.S. Public Health Service. ATSDR's mission is to prevent or mitigate adverse human health effects and diminished quality of life resulting from exposure to hazardous substances in the environment.

The public health assessment is the cornerstone ATSDR uses to address public health issues associated with hazardous waste sites. The document discusses available information about site-related hazardous substances and evaluates whether exposure to them -- in the past, present, or future -- might cause adverse health effects in members of the community.

ATSDR is responsible for preparing public health assessments according to the Comprehensive Environmental Response Compensation and Liability Act (CERCLA or Superfund) section 104 (i)(6) (42 U.S.C. 9604 (i)(6). As mandated by that law, ATSDR conducts public health assessments of hazardous waste sites listed or proposed for listing on the U.S. Environmental Protection Agency's (EPA) National Priorities List (NPL). ATSDR also responds to requests (petitions) to conduct public health assessments.

Three primary sources of information are used in a public health assessment: environmental data, community health concerns, and health outcome data. ATSDR does not routinely perform environmental sampling. The environmental data used in public health assessments are provided by the Department of Defense (DOD) component involved; EPA, state, and local environmental and health agencies; and other groups or individuals. In addition, ATSDR health assessors conduct site visits to observe firsthand current conditions at the site, land use, public accessibility, and demographic characteristics of the nearby community.

Concerns the community has about health are gathered to determine if specific health effects are being experienced by people who live or work near the site. Information from the public also helps ATSDR determine how people may have been or might be exposed to hazardous substances in the environment. Throughout the public health assessment process, ATSDR staff members talk with people living or working at or near the site about their site-related health concerns. Other sources of community health concerns are records from the installation's Public Affairs Office, EPA's Community Relations representative, and state and local health and environmental agencies.

Health outcome databases document health effects that occur in populations. Those data, which come from sources such as state tumor registry databases, birth defects databases, vital statistics records, or other records, may provide information about the general health of the community living near a site. Other more specific records, such as hospital and medical records and records from site-specific health studies, may be used.

Demographic data that provide information on population characteristics (e.g., age, sex, socioeconomic status) are used when analyzing health outcome data.

ATSDR identifies actual and perceived site-related health effects and the level of public health hazard posed by the site. ATSDR then makes recommendations to the appropriate DOD components, EPA, and relevant state and local agencies on preventing or alleviating human exposures to site-related contaminants. When indicated, ATSDR identifies a need for any follow-up health activities -- such as epidemiologic studies, registries or community health education. Finally, ATSDR provides a mechanism to re-evaluate health issues as site conditions change (e.g., after site remediation or changes in land use) or when new data or information are available.

A public health action plan (PHAP) is included in the public health assessment. It contains a description of actions ATSDR and other parties will take at and in the vicinity of the site. The purpose of the PHAP is to provide a plan of action for preventing and mitigating adverse human health effects resulting from exposure to hazardous substances in the environment. ATSDR annually monitors the implementation of the plan. Public health actions may include, but are not limited to, restricting site access, sampling, surveillance, registries, health studies, environmental health education, and applied substance-specific research.

Public health assessments are distributed in three phases: an initial release (red cover), a public comment release (brown cover), and a final release (blue cover). The initial release document, which is prepared as part of the process of gathering, analyzing, and drawing conclusions and recommendations from the vast amount of information evaluated in a public health assessment, is provided for review and comment to the DOD component involved, EPA, and state and local environmental and health agencies. This release gives agencies the opportunity to comment on the completeness of information they have provided and the clarity of the presentation. The initial release comment period lasts 45 days. Following the initial release, ATSDR prepares the document for distribution to the general public. The public is notified of the document's availability at repositories (e.g., libraries, city hall) in the site area through advertisements and public notices in newspapers. The comment period lasts 30 days. ATSDR addresses all public comments and revises or appends the document as appropriate. The final public health assessment is then released; that document includes written responses to all public comments.

A public health assessment is an ongoing process. ATSDR revises final documents if new information about the environment, community health concerns, and health outcome data becomes available and is found to modify previous conclusions and recommendations. For more information about the ATSDR public health assessment process and related programs please write to:

Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry
1600 Clifton Road (E-32)
Atlanta, Georgia 30333


Naval Station Treasure Island, Hunters Point Annex (HPA), an inactive Naval shipyard located on a peninsula in the San Francisco Bay, San Francisco, California, was listed for base closure in 1990. In 1986, in preparation for HPA's annexation to Naval Station Treasure Island, Navy contractors conducted extensive soil and groundwater testing to characterize the nature and extent of contamination. Metals, pesticides, radium-226, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds, semivolatile organic compounds, petroleum products, and asbestos have been found in various media such as soil, groundwater, surface water, air, and sediments. Based on the results of the testing, HPA was placed on the U.S. Environmental Protection Agency's (EPA) National Priorities List in 1989. Agency for Toxic Substances and Disease Registry (ATSDR) health assessors conducted this public health assessment to evaluate whether exposure to these contaminants presented or may present a risk to human health.

Navy contractors have identified 58 HPA areas where there may be contamination; investigations at these areas are ongoing. The site has been divided into five parcels, A-E.

ATSDR identified four parcels (B-E) where there was and is the potential for human exposure and investigated the available information on those parcels thoroughly. Of these, ATSDR concluded that Parcel E (the Industrial Landfill Area and the Bay Fill Area) posed a public health hazard due to past exposure to contaminants in the soil (see Table C-1 for ATSDR Conclusion Categories). ATSDR has determined that while the landfill was operational, landfill operators, Triple A workers, Navy personnel and their children, tenants, and trespassers were exposed to metals, PCBs, PAHs, and radium-226. Exposures to lead, PCBs, and PAHs were of public health concern. Those individuals may have incidentally ingested and breathed enough contaminated soil and dust while moving earth, walking through the landfill areas, or playing along the shoreline to increase their risk of developing cancer. The increased risk for landfill operators, whose exposure was greatest, is 1 excess cancer case above the normal background incidence for every 10 exposed people over a lifetime. ATSDR health assessors predicted that noncancer adverse health effects may occur in those populations as well. Exposure to radium-226 posed no apparent health risk.

ATSDR has ranked the remainder of HPA as an indeterminate public health hazard for the following reasons: 1) The data are incomplete because many areas of HPA have not yet been fully characterized; 2) Existing data provide no definite indications of other current or past exposures; 3) Full evaluation of the level of health risk depends on decisions about the future use of the site as well as having complete data on the levels of contaminants. Therefore, ATSDR included a description of those sites and listed the data needed immediately. However, two situations require more immediate data collection because of the potential for ongoing exposures: the aquatic food chain and methane gas in the landfill areas.

There is a potential for exposure to metals, pesticides, and PCBs through the aquatic food chain. The aquatic food chain near and at HPA may be contaminated, and people may be eating contaminated fish. Initial sampling indicated that the landfill areas and associated shoreline are more contaminated than many other HPA areas, and some media (e.g., stormwater) appear to be toxic to test organisms. The Navy's Environmental Sampling and Analysis Plan, however, provided limited information on the type and extent of contamination present in sediments, storm drains, and bay water and on the effects these media have on test organisms. Because subsistence, commercial, and sport fishing take place near the HPA, this potential exposure may be of health concern depending on the exposed population's fishing practices and fish-consumption rates.

Methane gas, detected in the Industrial Landfill, Waste Oil Disposal Site, Disposal Trench Areas, and other areas poses a current explosion hazard for drillers installing wells or boring soil. In addition, the methane pocket in the Waste Oil Disposal Site is located on the site boundary line; the extent of the pocket off site has not been determined. There is a potential for gas migration off base at the Industrial Landfill. In the future, methane may migrate into any new structures built on the Industrial Landfill, Disposal Trench Areas, and Waste Oil Disposal Site and could thereby present a further explosion hazard.

The level of health hazard posed to current or future occupants of HPA depends not only on the levels of contamination but also on the uses to which the land is put. Because Congress mandated the Navy to transfer portions of the base to the city of San Francisco, the intention is to reuse the site; and these decisions will have health as well as economic implications. For example, permitting restaurants or day-care centers to operate in buildings in parcels B-E could pose a health hazard, although using the parcels for light industry may not. Renovation and environmental cleanup activities themselves can change the level of health risk because excavation and construction can unearth subsurface contaminants that might then pose health risks to base tenants, remediation and utility workers and area residents. Dust and airborne soil particles may also pose a health threat to people using HPA because high levels of lead and other metals have been detected in surface soils at some areas.

In general, the air quality in Hunters Point/Bayview does not pose a health hazard for local residents. However, within the base itself, preliminary air data collected at the landfill (at an upwind background air monitoring station) indicated concentrations of pesticides (aldrin, dieldrin, heptachlor, endrin, and DDT) at levels of health concern. The source of the pesticides is unknown. ATSDR cannot determine whether these samples represent daily ambient conditions, since this finding was based on a single initial screening.

The community expressed concerns about air quality at Hunters Point/Bayview, increases in morbidity and mortality rates, potential exposures to contaminants in groundwater, and cleanup procedures for the HPA. ATSDR determined that the air quality is generally good, there is no noticeable increase in the Hunters Point/Bayview community's mortality and morbidity rates, and there is little chance that the community's groundwater will become contaminated. Regulatory agencies such as the EPA, the California State EPA, the California Department of Toxics, and the California Water Quality Control Board oversee the cleanup activities at HPA to ensure that cleanup levels achieved will leave the area safe for the intended future use. ATSDR will review workplans for future reuse if requested.

Further actions recommended by the ATSDR Health Activities Recommendations Panel include the following:

LANDFILL EXPOSURE: No public health actions are planned as a result of the landfill workers past exposures to PCBs, PAHs, and lead, because all personnel records from the period when the shipyard was active have been archived and, according to the Navy, can not be retrieved. Therefore, it is unlikely that the individual landfill operators can be identified or individual levels of exposure evaluated.

FOOD CHAIN: Further toxicity tests and tissue analyses should be conducted in sediments, fish, and shellfish to determine whether contaminant levels are above Food and Drug Administration or EPA levels. If contaminant levels of concern are detected in fish and shellfish, people who eat fish caught at or near HPA should receive community health education explaining the health implications of possible exposures to contaminants bioaccumulated by fish and shellfish.

FUTURE EXPOSURE: If other environmental data that indicate people are being exposed to hazardous substances at HPA become available, ATSDR will reevaluate the need for additional follow-up public health actions. The Public Health Action Plan defines the implementation of the health education.


A. Site Description and History

Naval Station Treasure Island, Hunters Point Annex (HPA) is in the southeastern part of San Francisco, California on a peninsula extending into the San Francisco Bay (Figure B-1). It is bounded by an off-site residential and industrial community, the Hunters Point/Bayview area, on the west. HPA covers 965 acres, 500 acres on land and 465 acres in the bay. Originally, the land mass of HPA was less than 100 acres (1). The Navy increased the land mass of the base primarily by using earth from the surrounding hills as fill (Figure B-2). Some of the Bay Fill Area and the Industrial Landfill is composed of sandblast waste and miscellaneous industrial debris (2). Most of the base is fenced to keep area residents from trespassing, although some areas are accessible from the shore by boat or by foot.

Naval operations at HPA began in 1941 near the start of WWII. The Navy increased ship building operations to quicken production of liberty ships during WWII. From 1941 to 1974, the principal facility activities were ship building; naval ships and submarines were also modified, maintained, and repaired. In addition to repair activities, the facility was used for base housing, naval ordnance training exercises, radiological defense research, and research on exposure to radioactive fallout (1, 3).

In 1946, a group, designated as the Naval Radiological Defense Laboratory (NRDL), was detailed to arrange for the decontamination and disposition of several ships that had returned from nuclear weapons tests at the Bikini Atoll in the Marshall Islands. NRDL's mission was the study of nuclear weapons effects and the development of counter measures. NRDL was operational from 1946 until 1969 (3). Several of the buildings were used for radioactive laboratory operations, cyclotron operations, animal research studies, material storage, and/or processing by NRDL (4, 5). NRDL sites are found in Parcels B, C, D, and E (Figure B-2). Buildings that are NRDL sites are listed in Appendix C, Table C-2.

Radionuclides were used in several of the HPA buildings. Table C-2 lists the buildings known to have been used by NRDL. Radioactive wastes generated by NRDL were placed in 55 gallon drums and temporarily stored in a fenced, controlled, and monitored area at HPA. Those drums were periodically transported on a barge, taken out to the Farallon Islands, off the California coast, and released into the sea. The drums were encased with concrete and sunk to a depth of 1,000 fathoms (2).

During the disbandment of NRDL, Nuclear Regulatory Commission (NRC) accepted the Navy's release of the NRDL buildings to unrestricted uses. Most of the buildings used by NRDL are in ruins. The NRC was the agency responsible for releasing buildings for unrestricted use, but the Navy conducted the actual decontamination of those buildings. NRC retains the records pertaining to NRDL activities. The Navy and the California Department of Health Services (CDHS) are researching archived NRC and naval records to verify documentation of previous release for unrestricted use (6). CDHS is under contract to the Regional Water Quality Control Board (RWQCB) to provide radiological support to research along with the Navy archived NRC and naval records.

HPA remained active until 1974, when it was placed on industrial reserve. The majority of HPA was leased to Triple A Machine Shop, Inc. from 1976 to 1986 during which time the base was used for ship repair. During this period, Triple A sub-leased HPA buildings to many small businesses. Allegations of improper waste disposal practices by Triple A were reported and in 1986, twenty on-site areas were investigated by the San Francisco District Attorney (7). The company has been accused by the city and county of dumping hazardous waste in various areas on site. The city won the court case, which is now undergoing appeal (8). The Navy is including all the suspect dump areas into their Remedial Investigation/Feasibility Study (RI/FS) work plans (1).

In 1981, the Department of Defense (DOD) developed the Installation Restoration Program (IRP) to investigate hazardous material disposal sites at DOD facilities. The Navy is conducting investigations and remediation under the IRP.

In 1986, HPA was taken over by the Navy to be developed as an annex to Naval Station Treasure Island. Extensive soil and groundwater testing took place to characterize the nature and extent of the contamination. Table C-3 lists an overview of installation investigations. Based on the results of the testing, HPA was placed on the U.S. Environmental Protection Agency's (EPA) National Priorities List (NPL) in 1989. The initial Federal Facilities Agreement (FFA) was signed January 22, 1992, between the Navy, EPA, and the State of California, Department of Toxic Substances Control (DTSC) and the Regional Water Quality Control Board (1).

The FFA outlines activities to be accomplished and presents a proposed time line. In addition to being placed on the NPL, HPA was listed for installation closure in 1990 by the Base Realignment and Closure Commission. The Navy was directed to remediate HPA and make it available for nondefense use (1).

The Navy has designated 58 areas of concern at HPA including 20 Installation Restoration (IR) areas and 38 preliminary assessment (PA) areas. Four groups were designated and called operable units (OU) (Table 1). The OUs are not geographically arranged, but instead were grouped into OU areas with similar contaminants. There were also six groups designated.

Most of the buildings and the surrounding areas are considered areas under investigation or PA areas. Industrial waste generating activities took place in many of the buildings (9, 10, 11). As of June 1993, all PA areas were in the site inspection stage. Table C-3 lists many of the major past and current HPA investigations; many investigations are ongoing.

Table 1. Designation of Operable Units and Associated Installation Restoration and Preliminary Assessment Areas

OU I Group 1
IR-1/21 - Industrial Land Fill/Area Southwest of Building 801
IR-2 - Bay Fill Area
IR-3 - Oil Reclamation Ponds
OU II Group 2
IR-6 - Tank Farm
IR-8 - Building 503, PCB Spill Area
IR-9 - Pickling and Plating Yard
IR-10 - Battery and Electroplating Shop
OU III Group 3
IR-4 - Scrap Yard
IR-5 - Old Transformer Yard
OU IV Group 4
IR-7 - Sub-Base Area

Group 5
IR-11 - Building 521, Power Plant
IR-12 - Disposal Trench
IR-13 - Old Commissary
IR-14 - Oily Waste Disposal Site
IR-15 - Oily Waste Ponds and Incineration Tank
IR-17 - Drum Storage and Disposal Site
Group 6
IR-18 - Waste Oil Disposal Site
IR-20 - Building 156 and Former Waste Storage Yard
IR-22 - Buildings 368 and 369
All PA areas, See Appendix D
Adapted from the Draft Final Ecological Risk Assessment Work Plan. Naval Station, Treasure Island Hunters Point Annex, San Francisco, California. September 9, 1992 (12).

The initial FFA is being renegotiated because it did not focus on the future site turn over to the city and rapid cleanup of the base. The initial FFA strategy involved the cleanup of areas scattered throughout the base and did not include many of the PA areas. An interim amendment FFA was signed in May of 1993. The final FFA is presently being negotiated. The Navy adopted a plan for geographic units. The Navy's plan to use geographic units was approved by the EPA, the DTSC and the RWCQB. Land parcels will be remediated and offered to the city and county of San Francisco (13). Figure B-2 shows the Navy's adopted parcels arrangement and Table 2 lists the Parcel designations. The Navy's negotiations for the proposed parcelization of HPA and associated schedules with EPA and the state are not yet complete. Schedules for parcel cleanup have not been finalized.

Table 2. Parcel Designations

Parcel Acreage Areas Within Parcels
A 90 (approximate) PA-19, PA-41, and PA-43
B 65 IR-6, IR-7, IR-10, IR-18, IR-20, PA-23, PA-24, PA-25, PA-26, PA-31, PA-42, and PA-46
C 60 PA-27, PA-28, PA-29, PA-30, PA-49, IR-57, and PA-58
D 125 IR-8, IR-9, IR-17, IR-22, IR-32, PA-33, PA-34, PA-35, PA-36, PA-37, PA-38, PA-39, PA-44, PA-48, PA-53, and PA-55,
E 135 IR-1/21, IR-2, IR-3, IR-4, IR-5, IR-11, IR-12, IR-13, IR-14, IR-15, PA-16, PA-40, PA-47, PA-54, PA-56, and PA-52
Site Wide PA-45 (Steam Lines), PA-50 (Storm Drains and Sanitary Sewer), and PA-51 (Former Transformer Sites)

The RI/FS process for the parcels will define the nature and extent of contamination and determine what action, if any, should be taken to remediate those areas. The Navy has prepared Alternative Selection Reports for Group 5, OUs II, III, IV, and V; Ou V includes Group 5 and also includes all other sites not in OUs I, II, III, and IV (14). The OU-specific Alternative Selection Reports describe the nature and extent of point sources of chemicals. The Navy and the regulatory agencies will decide on any necessary interim actions prior to completion of HPA investigations (15).

ATSDR identified 10 areas where there was or is the potential for human exposure if not mitigated. These sites will be the primary focus of the assessment. Appendix D describes the remaining areas.

Industrial Landfill (IR-1/IR-21)/OU I/Parcel E

The Industrial Landfill is in the southwestern portion of HPA. This area is approximately 350 feet northwest of Spear Avenue and is bounded by the bay on the southwest and the HPA property line on the northeast and northwest (Figures B-2 and B-3). The landfill is divided into an east and a west section topographically. The landfill covers 36 acres and was used from 1958 to 1974, although Triple A reportedly disposed of unknown wastes in the landfill after that time (16). While the landfill was operational, approximately 20 acres of San Francisco Bay were filled with waste material (3).

Wastes known to have been disposed there include 21,000 gallons of liquid chemical waste, 500 cubic yards of asbestos, domestic wastes and refuse, building construction and demolition wastes, dredge spoil materials, sandblast wastes, shop industrial and chemical and solvent wastes, and low-level radioactive wastes from shipboard radium dials and electronics equipment (2, 16). It is unknown when the radium sources were deposited at the landfill. The radium sources are in various forms including dime-sized, sealed, glass discs with a spot of radium in the middle, ceramic and larger glass wafers, hollow ferrous discs with a glass covers, and in the form of quarter-sized metal sources with back plates (17, 18).

After landfill operations ceased in 1974, the area was covered with clean fill and seeded with grass. A stormwater interceptor line was constructed to prevent surface runoff from flooding the landfill. Soon after the landfill was covered, leachate was discovered migrating from the landfill into the bay (16). In 1975, an unsuccessful attempt was made to build a slurry wall to avert the leachate flow. The slurry wall did not work because buried solid waste debris (concrete, wood, etc.) prevented excavation and construction in the landfill (2).

Access into the landfill is by dirt roads which encircle the area. Guards control the majority of the vehicular access to HPA through a main gate. In December 1991, a fence restricting access was installed along the southwestern portion of the base to include IR-1 (Figure B-2), but not along the shoreline.

ATSDR is concerned that past exposures to contaminants in surface soil could have been at levels of health concern. Additionally, contaminants leaching into the bay may have or could be contaminating fish and shellfish.

Bay Fill Area (IR-2)/OU II/Parcel E

Found on the southern shore, the Bay Fill Area is bounded by J Street on the northeast and the bay on the south and the southwest (Figure B-3). This area extends northwest to Spear Ave. This area was used as a landfill from 1945 to 1978. During the 1980s, a high rise bachelor enlisted quarters (BEQ), Building 600, was built on the fill area and used by sailors until 1986. The BEQ housed up to 500 sailors.

The Bay Fill Area was used for disposal of assorted shipyard wastes which include sandblast wastes containing copper, lead, paint scrapings, and radium sources. It was thought that sandblast waste from ships exposed to nuclear detonations at Bikini Atoll may be present, but current radiological testing has not identified levels of radioisotopes associated with disposal of those materials (4). Additional wastes disposed of in IR-2 include waste oils, chemicals, building and ship materials, and acid tank roofs (16).

The BEQ, IR-3 and the Oil Reclamation Ponds are the only structures remaining in this area. There are existing roads to this area. The Bay Fill Area is within the fenced restricted access area, but is accessible by water (Figure B-2).

ATSDR is concerned that past exposures to contaminants in surface soil could have been at levels of health concern. Additionally, contaminants leaching into the bay may have or could be contaminating fish and shellfish.

Oil Reclamation Ponds (IR-3)/OU II/Parcel E

The Oil Reclamation Ponds are within the Bay Fill Area, and are approximately 30 feet from the bay. Two oil reclamation ponds were constructed in 1944 along the southern shore of the Bay Fill Area. Those unlined ponds were used to store waste oil generated by the ships and various base industrial shops. The waste oil was heated using subsurface steam lines and was pumped out of the ponds. In the past, the base contracted to have the heated waste oil removed three times a year (19). Other waste products deposited in the ponds include bilge water, solvents, caustic soda, ethylene glycol, and chromates. The ponds were filled without first being cleaned. Triple A reportedly deposited sandblast wastes over the pond (16). Soil and groundwater treatability studies are currently being performed, prior to the remediation of IR-3.

ATSDR is concerned that contaminants in soil and groundwater are leaching into the bay and may contaminate fish and shellfish.

Scrap Yard (IR-4)/OU III/Parcel E

IR-4 includes the Scrap Yard, Triple A Site 3, and an area southwest of the Scrap Yard where scrap material and automobiles were stored during Triple A's occupancy (20). The area is near the intersection of Spear and Crisp Avenues (Figure B-3), in the west-central portion of the base. The Scrap Yard is 650 feet by 100 feet in size, narrow and rectangular-shaped (16). There are two buildings within IR-4: Building 807 (partly burned down) in the Scrap Yard and Building 811, (former diesel station) at Triple A Site, neither of which are currently used.

Most of the property is fenced, railroad tracks border the northwestern edge. At the junction of Spear Avenue, 6th Street, and I Street, there is an access gate leading into the yard. Total area investigated is about 5 acres in size. The Scrap Yard and the Triple A areas are paved with the pavement ending about 50 to 100 feet west of the Scrap Yard; the area where scrap material was observed in an aerial photograph is not paved. The pavement in the area west of the Scrap Yard is in poor condition with loose soil and vegetation covering the surface of the area. The Scrap Yard area was built on fill material.

The Yard was operational from 1954 to 1974, and was used to store submarine battery lead and copper and electrical capacitors containing polychlorinated biphenyls (PCBs). Reportedly 7,000 pounds of lead and copper residues were washed into the soil during this time (16). Also 250 gallons of oil containing PCBs from crushed capacitors may have been spilled in the area (16). During Triple A's occupancy of HPA, scrap metal and other debris were stored at the Scrap Yard, at times the debris was several feet deep (20).

ATSDR is concerned that present and future exposures to contaminants in surface soil if not mitigated could be at levels of health concern.

Old Transformer Storage Yard (IR-5)/OU III/Parcel E

The Old Transformer Storage Yard is between I Street and 6th Street, east of I street and southeast of the intersection of 6th and R streets (Figure B-3). The area is rectangular and covers about 1 acre. There are no buildings on IR-5. The Old Transformer Storage Yard and surrounding area comprise about 5 to 6 acres. There are three detectable concrete pads in the northern portion of the area. The Navy encountered pavement at a few locations, but found it difficult to delineate paved areas because of debris, loose soil and vegetation (20).

From 1946 to 1974, electrical transformers were stored in an unpaved open yard about 400 feet north of Building 704. It is estimated that 6 to 8 transformers per year were stored at this location over a 30 year period (21). Transformers containing PCB oils may have leaked into the soil (20). The base contracted to remove transformers off site (16). Triple A also used this area during their HPA occupancy (20).

ATSDR is concerned that present and future exposures to contaminants in surface soil if not mitigated could be at levels of health concern.

Disposal Trenches and Salvage Yard (IR-12)/Group 5/Parcel E

The Disposal Trenches and Salvage Yard is between Spear Avenue and J Street on the base's southwestern side (Figure B-3). It is an unpaved open area, a little more than 6 acres. Railroad tracks run from Site IR-4 through the center of the Disposal Trench Area. The eastern portion of the area was used by Triple A and the Navy as a salvage yard. Much of the ground is stained with oil from former chemical spillage (22). Leaking tins of oil and greenish liquids and possible asbestos lagging were observed on the ground in 1986 (16). At present, small pieces of metal debris are scattered about the site and some ground staining is visible (23).

Allegedly two waste disposal pits were excavated and used by Triple A in the southern portion of the area. Asbestos insulation, chlorinated solvents, corrosives, lead based paints, lead, and acid from batteries may have been disposed of here during Triple A's leasing of HPA (7). At least one trench (about 3 yards deep, 10 yards wide, and 30 yards long) was excavated and filled with waste materials, including acids, bases, chlorinated solvents, lead-based paints, paint chips and sludges, and paint cans (23). An estimated 2,000 gallons of liquid waste were dumped into the trench, as solid waste from ship repair and building maintenance (23). Also a concrete drum crushing pad adjacent to the eastern boundary of the disposal trenches along Sixth Avenue was used to demolish 55-gallon drums. The drums may have contained hazardous substances (22).

The San Francisco Regional Water Quality Control Board (RWQCB) requested a Solid Waste Air Quality Assessment Test (SWAQAT) investigation. The RI at IR-12 is intended to meet the specifications of the Caldron legislation (California Water Code 13273) for hydrogeologic evaluations of landfills and must include the following: a work plan approved by the RWQCB prior to initiating field investigations, vadose zone monitoring, installation of at least four groundwater monitoring wells, quarterly sampling and analyses for the required parameters for at least one year, and a report detailing the results of the SWAQAT. The SWAQAT was conducted from 1988 through 1989. One shallow vadose zone well was installed, methane was detected at a concentration of 46 percent (22). The SWAQAT results did not indicate the presence of any landfill gas or surface and subsurface migrations at IR-12 (23, 24).

ATSDR is concerned that the methane detected at IR-12 if not mitigated poses a physical hazard.


PA-52 consists of about 3,200 feet of railroad right-of-way that extends off site west of Parcel E (Figure 2), along Crisp Avenue, and beyond the end of the road (25). The right-of-way lies outside of the HPA boundary and is owned by the Navy. The Navy used and maintained the site until they leased the site to Triple A in 1976. The site is currently used by the Golden Gate Railroad Museum for transporting trains to their restoration area on site in Parcel E (25). Several small businesses are located along this right-of-way (11). Dumped household items such as 5-gallon containers of paint, resins, and unidentified materials, oil and paint spills, and automotive parts were observed in several areas. The track leads to an on site lumber transfer yard (11).

ATSDR is concerned that present exposures to contaminants in surface soil could be at levels of health concern. In addition, if not mitigated, contaminants in surface soil could pose a future health concern.

Tank Farm (IR-6)/OU II/Parcel B

The Tank Farm (IR-6) is on Lockwood Street north of Robinson Street (Figure B-3). It was constructed for use as a diesel fuel and lube oil facility and used from 1942 to 1974. Fuel and oil were distributed via underground utility lines to berths north and northeast of the area (26). Triple A also used the Tank Farm area until 1986. There were eight vertical 15,000-gallon tanks in a bermed area and one 240,000-gallon tank in a second bermed area. Petroleum hydrocarbons were stored in the 240,000 gallon tank and in two, 15,000-gallon tanks. Those tanks have since been removed. Stoddard solvent (used for degreasing, thinning paint, and in machine and automobile shops) may have been stored in two of the 15,000-gallon tanks (27). A spill occurred in 1944 when a 15,000 gallon vertical tank ruptured releasing hydrocarbons which overflowed the containment berms. Other facilities located in IR-6 included a pump house (Building 112) and equipment including a sump, and associated underground oil transport piping. Lube oil facilities included one tank in a third bermed area, an additional pump house (Building 111) and an empty sump, and concrete tank supports for eight horizontal tanks (28). Buildings and tanks were removed in April 1993 (29).

The soil around the tanks is stained, with the greatest amount of staining beneath the vertical tanks (16). The area within the berm for the eight vertical tanks appears to be lined with an asphalt-like material that has deteriorated over time. A concrete vault located outside the pump house was apparently filled with diesel fuel (28). Access to IR-6 is restricted by a fence.

ATSDR is concerned that present and future exposures to contaminants in groundwater could be at levels of health concern.

Battery and Electroplating Shop (IR-10)/OU II/Parcel B

The Battery and Electroplating Shop was located in the northern corner of Building 123, on Lockwood Street (Figure B-3). Building 123 was constructed on fill. From 1944 to 1974, Building 123 was used for electroplating, battery storage and maintenance. Cyanide wastes and waste acids containing copper, lead, and chromates spilled onto the floor of Building 123 and in the dock loading area. Those waste materials went into the floor drain system which connects to the storm sewer system which discharges into the bay. Approximately 250,000 gallons of liquid plating wastes contaminated with heavy metals were poured into the floor drains (16). Cyanide wastes were disposed of in containers at the industrial landfill. Now PA-24, Building 124, an acid mixing plant, and several tanks were once located at the southeastern end of Building 123, but were removed between 1979 and 1981 (16). IR-10 is fenced and locked.

ATSDR is concerned that present and future exposures to contaminants in groundwater could be at levels of health concern.

Storm Drain and Sanitary Sewer System (PA-50)/Site Wide

A combined storm drain and sanitary sewer system was constructed, at HPA between 1942 and 1946. The system drained into the bay through 41 outfalls. In place from 1942 to 1976, the system was used to collect stormwater runoff, sewage, and industrial wastes from many locations and facilities at HPA. Industrial discharges included acids, bases, organic solvents, paint, PCB contaminated waste oil, heavy metals, and plating waste solutions (30). Currently, sewage is conveyed from 10 reaches to Pump Station A, and subsequently discharged to the municipal waste water treatment facility (31).

In 1958, in response to the current Federal Water Pollution Control Act requirements, partial separation and upgrading of the system took place. Sewage and storm drainage in the industrial areas and in the southwest portion of the installation were separated. Of the original 41 outfalls, 29 were converted to drain only the storm drain system while the remaining outfalls continued to drain combined storm and sanitary systems (30).

In 1973, RWQCB issued an order for the Navy to separate the two systems and discontinue current waste disposal practices. All the storm drain outfalls in the southern portion of HPA south of J street were combined and connected to a single outfall that discharge directly to the bay. In 1976, the project was completed (30).

During the Navy's Utilities Technical Study it was noted that Drainage Areas A and D, storm drain sanitary sewer systems, were still interconnected (9). The Navy is addressing interconnections where they actually exist. The Utilities Technical Study noted signs of industrial pollution throughout the system.

Field inspections conducted during 1993, indicate that sediment is accumulating in the system and that very poor pipeline conditions occur locally (31). All sediment samples collected contained elevated levels of organic contaminants. The variety and concentrations of metals detected in the storm drain sediments locally resemble metals detected in surface soil and sandblast samples collected as part of the building site investigations (31).

Field inspections also indicated that the sanitary sewer pipe line integrity varies and that part of the system appears to be acting as a "sink" because the shallow aquifer groundwater is above the pipeline (31). The Navy recommended further investigations of the hydraulic and chemical conditions in the Parcel C and D storm drain systems and removing contaminated sediment from seven catch basins (31, 32).

ATSDR is concerned that contaminants in soil and groundwater are leaching into the bay and may contaminate fish and shellfish.

Past and Planned Remediation

Numerous removals have or will take place on HPA. Some of the removals that have taken place include the removal of 1,500 cubic yards of PCB contaminated soil at IR-8, approximately 1,500 drums of chemicals, the Tank Farm tanks, and the removal of Tank S-505 and it contents. All known USTs at HPA have been removed or closed in place. On-going removal actions include removal of sand blast grit at PA-19, demolition and removal of the gardener's shed in Parcel A. A complete listing of the removal actions that have taken place can be found in the HPA administrative record.

B. Site Visit

The first HPA site visit was conducted by ATSDR headquarters staff, and Region IX representatives on March 27-29, 1991. Debris, including many physical hazards, was observed throughout the facility. During the site visit ATSDR staff made field observations on all IR areas and several PA areas. The base is fenced along the boundary the Navy shares with the city, however the facility is located on a peninsula in San Francisco Bay and access from the water by trespassers is possible. Guards control the majority of the vehicular access to the property through a main gate. The western portion of Parcel A, along Crisp Avenue, is accessible by vehicles without passing through the main gate. The Parcel A gate is open from 9:00 a.m. to 5:00 p.m. and is controlled jointly by the Navy and the File Safe Record Storage Company. No fencing or warning signs were posted along the shoreline. Most of the base areas are accessible to base tenants who are inside the boundaries of the shipyard. Base tenants are people who are leasing buildings or areas on site, but not living on site. Some areas, such as the Pickling and Plating Yard were fenced, signs of trespassing (trash piles, fires, etc) were noted during the site visit. Access to some base areas must be arranged with security personnel at the installation main gate. Keys to locked buildings must be obtained from the Installation Commanding Officer's building (11).

Although HPA no longer operates as an active maintenance shipyard, various small businesses currently lease approximately 20% (in the past up to 50%) of the buildings on the base. Several federal agencies also occupy HPA buildings; the Navy uses a building for administrative purposes. ATSDR noted the areas currently leased by artists and other small businesses and their proximity to contaminated areas. Artists and other small business operators, can enter HPA 24 hours-a-day and do not appear to be restricted in their movements once on the base. The restricted access fence was not in place during the site visit.

As a follow-up to the March site scoping visit, ATSDR staff visited HPA on June 22-25, 1992. ATSDR gathered additional information on site conditions, environmental monitoring programs, and locations of hazardous waste sources; met with base tenants and community representatives to discuss community health concerns related to the hazardous waste areas at HPA; and met with representatives from EPA, state and local health agencies, and appropriate base officials.

During the site visit, ATSDR staff walked through the former base housing area, the portion of HPA scheduled for first release to the city and county of San Francisco. Former base housing units are located on a hill, close to the HPA's northern boundary adjacent to the community of Hunters Point/Bayview. ATSDR staff noted signs of trespassing in the former base housing area. Currently, there are no occupied residential units at HPA. ATSDR observed an area of the boundary fence in the housing area that had been repaired where someone had cut a hole in the fence. Debris and high vegetation exist along the HPA fence line and hinder adequate perimeter patrol.

Since the last site visit, fencing had been placed between some of the more contaminated areas near the bay (Parcel E) and the remainder of the facility, see Figure B-2. ATSDR visited some of the areas that were being used by other federal agencies, areas leased by artists, and other small businesses, and noted their proximity to contaminated areas. Several base tenants were leasing buildings beside the Pickling and Plating Yard.

ATSDR expressed concerns to the commanding officer about citizens gaining access to the former base housing area, which is adjacent to the Hunters Point/Bayview neighborhood. The commanding officer stated that the Navy was contracting to cleanup the debris along the fence line and cut back the vegetation in the former housing area to allow for closer inspections to deter trespassing.

On August 31, 1992 ATSDR staff conducted an additional site visit to meet with Navy staff, contractors, and EPA. Public availability sessions were held on September 1 and 2, 1992, at the Southeastern Community Facility. Citizens reported numerous health concerns.

C. Demographics, Land Use, and Natural Resource Use


Demographic data provide information on population characteristics. Demographic information aids the public health assessment activities by helping define special risk populations. In addition to the traditionally collected information, relevant information about the special risk community members living near hazardous waste sites may include the number and location of schools, hospitals, day care centers, and nursing homes if off-site exposure is occurring, or could occur.

A three square mile area (including the site) is densely populated (see Appendix C, Tables C-4 and C-5 for census data). More than 75% of the population is black; the county average is 11%. The percentage of persons under age 10 in the Hunters Point/Bayview area is 19%, 10% higher than the rest of the county.

There are more than three persons per household (county average is 2.29 per household). Approximately 41.3% of all households are owner occupied. The high percentage of renters could be largely due to the high cost of housing in San Francisco.

Land Use

On Site

HPA has been used for over 100 years as a ship repair facility. HPA represents a large portion of the land available for development in the San Francisco area. The base is in an urban setting, the South Bayshore or Hunters Point/Bayview area.

The northern and eastern shores of HPA were used for ship repair with drydock and berthing facilities; the southern shore was not used for shipping activities. The remaining facility consisted of office, industrial and residential buildings. There is one Navy administrative building on the base, but no Navy shipyard activities are taking place. The waterfront facilities consist of 40 deep-water berths, 500 feet in length and 6 dry docks of various sizes (16).

Several shipyard buildings were subleased by Triple A Machine Shop to various small business, artists, light industrial firms and private warehousing companies. After Triple A left HPA, subleasees remained. Twenty percent of the buildings are being leased by several hundred tenants. Parts of HPA are leased by 84 small businesses including warehouses, a business service, a commercial kitchen, a restaurant, a construction company, an olive oil bottling plant, a bakery, a cabinet maker, a police athletic club, a helicopter landing pad at IR-7, and an antique railcar restoration company. Approximately 300 artists rent studio space on base (33). There are approximately 200 Navy personnel still working in one area. Joint Military Postal Activity-Pacific occupied buildings 606 and 439 during and after Operation Desert Storm. According to the Navy, children generally are not allowed on the base.

The Navy was mandated by Congress to transfer a portion of HPA to the city for 30 years. The congressional mandate expired on May 30, 1993 and has not been replaced. HPA has been approved and selected for closure and disposition by the Base Realignment and Closure Commission. Plans for property turn over to the city are continuing. The dates and portions of the base that will be turned over to the city are being negotiated between the city and the Navy, and a memorandum of understanding has been signed (34).

The San Francisco city planners have not made a final decision on the future uses of HPA, but the city is proposing Parcel A, an approximately 90 acre area adjacent to public access by the Hunters Point/Bayview neighborhood, as a potential residential and commercial area (35, 36). Of the 90 acres proposed for transfer to the city, 40 are in the low lying portion of Parcel A, which is proposed for commercial as opposed to residential use (37). Parcel A includes the former base housing area, administrative buildings, and two former NRDL sites. The city also identified Drydock 4 as a priority area for redevelopment (38).

Off Site

Hunters Point/Bayview is a community composed of residential, commercial, and industrial uses. A wood-chipping mill abuts HPA on the western boundary. A steam generating power plant is located about a mile north of HPA. There is a water bottling company within one-half mile of the base (see discussion below under Public Drinking Water). Candlestick Park and the Candlestick Point State Recreation Area are about one mile southwest of the site.

Natural Resource Use


An artificial fill layer forms the uppermost geologic layer below HPA. Exposed bedrock lies in the central upland ridge. The base is 70 to 80 percent covered by fill materials (26). The fill layer is composed of two types of material: materials derived from excavation of the bedrock ridge and from dredged bay sediments and, to a lesser extent, materials derived from industrial activities. The bedrock derived fill layer is composed of serpentine and associated ultramafic rocks and mixtures of serpentine and Franciscan sandstone, chert, greenstone, shale, and dredged bay sediments. Serpentine rock contains a naturally occurring mineral chrysotile, the most important source of commercial asbestos (39). Asbestos has been detected in air samples and will be discussed further in the Environment Contaminants section. In addition to asbestos, the serpentine bedrock contains naturally high levels of metals (39).


There are three aquifers at HPA, a shallow unconfined aquifer in the fill material, a confined aquifer, and the bedrock aquifer occurring in deposits. The shallow aquifer has been best characterized. Depth to groundwater in the shallow aquifer ranges from 2 to 12 feet. An aquitard (confining layer), composed of bay mud, varies from 0 to 50 feet in thickness, and separates the unconsolidated fill material and undifferentiated sands (shallow unconfined aquifer) from the underlaying undifferentiated sediments (confined aquifer). Hydrogeologic conditions in the undifferentiated sediment deposits and the effectiveness of the bay mud acting as an aquitard have not been fully characterized. The bedrock aquifer consists primarily of the upper part of the Franciscan Bedrock. Groundwater is sporadically present in the fractured bedrock beneath the unconsolidated sedimentary deposits and it is possible that contaminated groundwater from the shallow aquifer may migrate to the bedrock aquifer, where the bay mud is absent (26). Because of the low permeability, sporadic occurrence, and thinning of fractures, bedrock groundwater may be technically infeasible to pump and recover (40).

In the northern portion of HPA, groundwater flow in the shallow aquifer is generally away from the bedrock ridge, an area of higher elevation, towards the San Francisco Bay (26). In the southern portion of the base, groundwater flows inland towards some sections of the sanitary sewer collection system where the integrity of the sewer is poor. Groundwater collected by these lines in turn flows by gravity to Pump Station A (35, 36). Facility wide groundwater flow directions are complex due to the heterogeneity of the hydraulic properties of subsurface fill materials and effects of the buried sanitary and storm sewers. Local flow directions vary in some areas due to tidal influence and localized recharge from storm events (26).

Public Drinking Water

Public drinking water for the city and county of San Francisco is supplied from the Hetch Hetchy Reservoir in Yosemite National Park. The Navy conducted a well survey which identified 34 wells within two miles of the geographic center of HPA, and 91 within 3 miles (33). The uses of seven of the 34 wells are known. Three were reportedly installed for irrigation, two for monitoring purposes (cathodic protection), and two for industrial use (33). Of the seven wells, one irrigation well is active and one other well is inactive; the status of the five other wells is unknown. Community members have stated that irrigation wells are presently being used by area well owners (41). All wells on site are monitoring wells.

The Albion Mountain Springs Water Bottling Company is within one-half mile northwest of HPA on Innes Ave. Spring water that is discharged from naturally occurring geologic formations of the Franciscan bedrock is collected in two open reservoirs before being bottled. The spring is hydraulically distinct from the shallow aquifer and upgradient of HPA (42). In addition, the spring is topographically upgradient of HPA. The bottling plant is required to meet the California Bottled Water requirements which are listed in Section 103.35 of the Code of Federal Regulations (CFR) 21. Required chemical analysis of bottled water includes metals and pesticides, but does not include the other contaminants detected in HPA groundwater. The owners of the bottling plant state that water from the spring is from the California Sierra aquifer, traveling deep beneath the San Francisco Bay to wells that supply the bottling plant (42).

Surface Water

Natural resources use includes surface water and aquatic wildlife. Fishing, boating, and wind surfing are the primary recreational activities that take place on the bay. According to the Navy, extensive fishing takes place two miles north to two miles south of HPA, and swimming takes place infrequently (1). The area around Hunters Point/Bayview provides one of the few recreational angling opportunities in an area of industrialized and developed South San Francisco Bay shoreline, where public access for recreational fishing is extremely limited (43). Coastal fishing from public piers, coastal fishing from the shore, and fishing on the bay from sport boats all take place. The Navy reported that up to 150 people have been seen shore fishing near the HPA area at one time (33). The population fishing in the area has changed over the years. Only military personnel were permitted to fish off HPA when the base was operational (44). The India Basin area, 0.75 mile northwest of the center of HPA and the Hunters Point Power Plant area are popular fishing sites. Recreational angling has been observed throughout the year with no apparent seasonal pattern (43). Up to 200 boats can be anchored 50 to 200 yards off the HPA shore at one time (33). Subsistence fishing also takes place (45). Creel surveys conducted by Pacific Gas & Electric of anglers fishing near the Hunters Point Power Plant site indicated that recreation and food consumption were the primary reasons for fishing at the site (43). The Pacific Gas & Electric Power plant is located one mile north of HPA.

There are more than 100 species of fish inhabiting the San Francisco Bay estuarine system (46). Hook and line angling is the primary method of fishing in the area but, there is some throw net and jigging for anchovy, Pacific herring, and shiner surfperch. Chinook salmon, striped bass and American shad are found within the estuary and are anadromous; that is they live most of their adult life in the ocean and then return to spawn in the same fresh waters where they hatched (46). Striped bass is the primary game fish angled in the bay; there is a bay wide fishing advisory on striped bass (47). The most abundant species captured by hook and line recreational anglers include Pacific staghorn sculpin, brownsmooth hound, white croaker, striped bass, and shiner surfperch (43). California halibut, leopard shark, white and green sturgeon, brown rock fish, bullhead, splittail, and pompano are the other recreational fish found in the bay. Some fishermen have been observed digging bait (mud shrimp, small crabs, and polychaete worms) in intertidal mud flats (43). The amount of shellfishing that takes place in this part of the bay is unknown. Clamming takes place 10 miles south of HPA (44).

The southern bay area serves as a seasonal nursery ground for species such as smelt and herring, which spawn in the central portion of the bay and use the near-shore estuaries during the early part of their lives (48). Dungeness crab mate primarily in northern portions of the bay and spread throughout the bay as they mature, remaining close to shore in the vicinity of Hunters Point. Crabbing does take place near HPA (45). Several flat fish species e.g., flounder, also use the near-shore area as juvenile nursery grounds and as adult habitat (48). In the south bay area there is commercial fishing for herring and bait shrimp (49).

In 1992, the National Oceanic and Atmospheric Administration (NOAA) conducted an evaluation of the extent and magnitude of biological effects associated with chemical contaminants in the San Francisco Bay (50). Biological effects in fish and shellfish that were studied included examination of the liver and kidney for lesions, scope of growth, and water and sediment toxicity. The spatial extent and magnitude of adverse effects throughout the San Francisco Bay estuary were evaluated. NOAA observed significantly higher incidence of biological effects in the San Francisco Bay estuary when compared with other areas along the Pacific Coast. Findings of the NOAA study are presented in the Pathways Analysis section.

D. Health Outcome Data

Health outcome data (HOD) document health effects that occur in populations. The data can provide information on the general health status of the community living near a hazardous waste site. It can also provide information on patterns of specified outcomes. Some examples of health outcome databases are tumor registries, birth defects registries, and vital statistics.

CDHS maintains a Department of Vital Statistics, the California Tumor Registry of the Cancer Surveillance Section, and the California Birth Defects Monitoring Program. The Department of Vital Statistics gathers information on numbers of deaths, births, marriages, and divorces for the State of California. Variables included in the database are geographic location (city, county, town), age, sex, race, and cause of death.

The California Tumor Registry database is the central repository for all data on cancer cases gathered from the State's 10 regions. The registry is a state-wide, population-based cancer surveillance system that monitors the incidence of and mortality associated with specific cancers over time. The database was designed to permit detection of risks of cancer by geographic region, age, race, sex, occupation, type of cancer, extent of disease, treatment, and demographics. This information is currently available for Region 8, San Francisco County, for 1973 - 1990.

The California Birth Defects Monitoring Program is a registry of children who were diagnosed with serious birth defects before their first birthday. The database contains information by 47 diagnostic categories of birth defects and by four demographic factors: region of residence, sex, race, and mother's age. Data for births in military hospitals are not included in the program. As of December 1992, information was available for four regions: the Coastal Region, the Bay Area Region, North Central Valley Region, and South Central Valley Region. The birth defects information for San Francisco County in the Bay Area Region is only available for 1986 and 1987.


Community health concerns are gathered to determine if specific health effects are being experienced by people who live or work near the site. Information from the public also helps ATSDR determine how people may have been or might be exposed to hazardous substances in the environment. ATSDR held public availability sessions, which are informal "one-on-one" meetings where residents can voice their health concerns related to the site, with Hunters Point/Bayview area residents. Community health concerns are listed and addressed in the Community Health Concerns Evaluation section under Public Health Implications.

Next Section&nbsp &nbsp &nbsp &nbsp &nbsp Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #