PUBLIC HEALTH ASSESSMENT
MICHIGAN SITES OF RADIUM DIAL CONTAMINATION
AIRCRAFT COMPONENTS (MICHIGAN RADIOLOGIC)
(a/k/a D & L SALES)
BENTON HARBOR, BERRIEN COUNTY, MICHIGAN
H & K SALES (MICHIGAN RADIOLOGIC)
BELDING, IONIA COUNTY, MICHIGAN
The primary contaminants of concern at these sites are radium and the radioactive products of itsdecay, including radon. These contaminants have mainly been identified at the sites byinvestigators using a variety of radiation detectors. There is no information available indicatingthat any material sampled from the three Radium Dial sites has been analyzed chemically. According to the literature, the radium was most likely originally present as radium sulfate mixedwith a phosphor in a paint carrier.
Benton Harbor site
On September 26, 1994, DRH staff conducted a preliminary radiation survey of the BentonHarbor site. DRH and U.S. EPA Region V staff conducted a second supplemental radiationsurvey on October 20, 1994 (2). The results of these surveys are summarized in Table 2, below.
Gamma radiation levels in the office building, warehouse, and Quonset huts ranged frombackground levels (0.005-0.01 milliroentgens per hour [mR/hr]) to 5 mR/hr near certaincardboard boxes and wooden crates containing radioactive aircraft instruments. Elevatedradiation readings of 0.05 mR/hr were measured outside the basement windows of Buildings 1and 2. Aircraft gauges could be seen through the windows of the basement of Building 2 (2).
Significant surface contamination was detected in the carpeting near several doorways in Building5 (up to 23,000 disintegrations per minute(4) [dpm]/100 cm2), on a conveyor belt apparatus inBuilding 5 (~410,000 dpm/100 cm2), in a storage rack on a basement workbench (~3,900,000dpm/100 cm2), and several other discrete areas throughout the warehouse and Quonset huts. Both fixed and removable contamination exceeded applicable state regulatory limits. Beta/gammacontamination levels measured with a pancake probe ranged from about 2,300 dpm/100 cm2 toabout 3,900,000 dpm/100 cm2, compared to background levels of 700-1,150 dpm/100 cm2. Afew damaged aircraft instruments were found outside the basement door at the rear of Building 1and in another area between the small Quonset hut and the river. DRH personnel picked up thedamaged instruments, placed them in plastic bags, and placed them into one of the buildings onthe site. Ground contamination after the gauges were removed was measured to be 90,000dpm/100 cm2 (beta/gamma) outside the basement door and 300,000 dpm/100 cm2 between theQuonset hut and the river. Associated soil samples contained radium-226 contamination of19,300 picocuries per gram (pCi/g) and 11,500 pCi/g, respectively (2).
Radon levels in the basement and first floor of the office building were less than 4 picocuries perliter (pCi/L), but considered elevated above typical, expected levels (2).
On February 6 and 13, 1996, personnel from the U.S. EPA, a contractor for the U.S. EPA, andMDPH DRH conducted a site assessment of the Benton Harbor site as part of the planning for theremoval of the dials from the site. They did not enter the main floors of buildings 1 or 2 (seeFigure 3) for safety reasons. The radiation level around several small boxes of gauges in building3 was 0.08 mR/hr, and that around a conveyor in building 5 was 0.04 mR/hr and 410,000dpm/100 cm2 (beta/gamma) with a pancake probe. The radiation level in contact with gauges inthe basement of building 1 reached 16 mR/hr, and pancake probe measurements of beta/gammaradiation in the basement of building 3 reached 1,150,000 dpm/100 cm2. A floor drain in thebasement of building 5 exhibited 0.015-0.02 mR/hr gamma radiation and the floor around thedrain showed 14,000 dpm/100 cm2 alpha and 250,000 dpm/100 cm2 beta/gamma radiation. Aworkbench in the basement of building 5 exhibited 14,000 dpm/100 cm2 of beta/gamma radiation,and crates and boxes of gauges in the basement were emitting between 5 and 7 mR/hr at contact.
Crates of gauges in the larger Quonset hut measured 2.6 mR/hr of gamma radiation, and a bag ofinstrument knobs measured over 5,800,000 dpm/100 cm2 (beta/gamma) with the pancake probe. A small box of gauges in the smaller Quonset hut emitted 1.2 mR/hr. These results are alsosummarized in Table 2 (16).
On October 3, 1994, DRH staff conducted a preliminary radiation survey at the Belding site. DRH and U.S. EPA Region V staff conducted a second supplemental radiation survey of thewarehouse on October 21, 1994 (4). The results of these surveys are summarized in Table 3, below.
Gamma radiation levels measured in the warehouse ranged from background levels to 7 mR/hrnear certain cardboard boxes and wooden crates containing radioactive aircraft instruments. Atleast 3,000-6,000 radioluminous aircraft gauges are estimated to be stored at the site. A relativelyextensive area of the warehouse presented gamma radiation levels in excess of 1 mR/hr (4).
Surface contamination (beta/gamma activity) was measured with a pancake probe at severallocations in a range from about 4,600 dpm/100 cm2 to about 115,000 dpm/100 cm2. Contaminated areas included the stairway steps to a raised office area, the central (door #2)loading dock, cracks in the concrete floor, and desk top areas in the area near the loading dock. No surface contamination was found outside of the warehouse Rooms 1 and 2. Three pairs ofwork gloves displayed low-level contamination. Contamination levels were generally in excess of applicable state regulatory limits (4).
Radon levels measured in the building ranged from about 30 to 50 pCi/L, well above typical,expected background levels and the U.S. EPA's action level (4).
Inspection of the truck used for aircraft gauge shipments from Benton Harbor to Belding showedseveral areas of the truck bed contaminated in excess of applicable regulatory limits (4). Thetruck trailer has been taken out of service and the contaminated areas covered with wood andplastic, pending final decontamination.
On February 14, 1996, personnel from the U.S. EPA, a contractor for the U.S. EPA, and MDPHDRH conducted a site assessment of the Belding site as part of the planning for the removal of thedials from the site. They confirmed gamma radiation as high as 7 mR/hr in contact with crates ofgauges and beta/gamma activity from individual broken gauges as high as 6,900,000 dpm/100 cm2(also in Table 3) (18).
Surveys of the Belding property did not find any radioactive contamination outside the building.
The Bear Lake site
A preliminary radiation survey of the Bear Lake site was conducted by DRH staff on April 11,1995. Severe radium contamination was found in the basement workroom at the home. Asecond, more comprehensive survey was conducted on April 20, 1995, by DRH and U.S. EPAstaff. The results of these surveys are summarized in Table 4, below.
During the second survey, the investigators found extensive removable and fixed radiumcontamination throughout the home in virtually every accessible area, including floors, walls,furniture, and clothing. Indoor radon levels ranged from 45 to 46 pCi/L in the basementworkroom and 19 to 22 pCi/L in first floor living areas. Alpha radiation levels ranged from 1,400dpm/100 cm2 to 41,000 dpm/100 cm2 on the first floor and up to 2,400,000 dpm/100 cm2 in thebasement. Beta-gamma radiation levels ranged from 2,800 dpm/100 cm2 to 580,000 dpm/100cm2 on the first floor. Ambient gamma radiation levels, including background, ranged from 0.04-0.24 mR/hr on the first floor, up to 1.5 mR/hr in the basement workroom, up to 3.0 mR/hr insidethe detached garage, and 1.1 mR/hr along the exterior of the detached garage (8).
U.S. EPA staff discovered roof contamination, probably from chimney emissions. Back yard soilcontamination was found up to 6,000 pCi/g of radium-226 (subsurface, as much as 6 feet deep),apparently resulting from discharge from a basement spray paint chamber exhaust vent. Near-surface soil samples contained up to about 2,000 pCi/g of radium-226. Sludge samples collectedfrom two septic tanks in the backyard contained up to 576 pCi/g of radium-226 (8).
Well water samples collected at the Bear Lake site contained less than 0.2 picocurie per liter(pCi/L) radium, considered within normal background ranges. The U.S. EPA MaximumContaminant Level (MCL) for radium in drinking water is 5 pCi/L (8, 19).
After the demolition and removal of the house, and the excavation of contaminated soils, theDRH collected additional soil samples to verify the success of the clean-up. DRH analysis found no contamination above MDPH/MDEQ guidelines for unrestricted use (9).
In January 1995, four of the most highly exposed workers at the H & K Sales warehouse (Beldingsite) were scanned for retention of potentially ingested radium in a cooperative effort with staff ofthe Consumers Power Company's Palisades Nuclear Plant near South Haven, Michigan. The testsfound no detectable amounts of radium (4). In September 1995, three former workers at AircraftComponents, Inc. (the Benton Harbor site), whose job descriptions indicated that they were likelyto have been exposed to radioactive material, underwent whole-body radiation scans at ArgonneNational Laboratories near Chicago, Illinois (20). The scans found no radioactive material in their bodies above normal background levels (21).
Preliminary radiation surveys of other Benton Harbor area buildings and sites previously used byAircraft Components, Inc. resulted in elimination of two buildings from consideration for furtheraction. Several other buildings, all located on or adjacent to the Benton Harbor airport, werefurther assessed based on elevated gamma levels found on the site grounds and the discovery ofburied gauges outside the buildings. Slight interior contamination was found, but additionalsurveys are needed to fully evaluate the contamination (2).
Soil samples collected from a residential property next to the Bear Lake site contained someradium contamination. The roof on a garage on the property was also found to be contaminated(8). The U.S. EPA excavated and removed the contaminated soil and removed and replaced theroof. The U.S. EPA and MDPH-DRH have declared the property clean of contamination (22).
In about 1990, the owners of the Bear Lake site gave a carpet remnant to another resident of theBear Lake area, who used the remnant in their house. In November 1995, DRH staff conducted aradiation survey of the other resident's home and determined that the carpet remnant, a vacuumcleaner dust bag, and the floor beneath the carpeting were contaminated with radium. DRHconfiscated the carpet and dust bag, and U.S. EPA staff removed and replaced two areas of woodfloor in the house (22, 23).
In response to a concern that potentially contaminated septic wastes from the Bear Lake sitemight have been surface disposed on a neighboring property, DRH staff surveyed the property inquestion. No radioactivity above background was found.
In response to allegations that the owner of the Bear Lake site might have disposed ofcontaminated trash at another property he owned in the area, DRH staff conducted a preliminaryradiation survey at the second property in December 1995. No radiation levels above backgroundwere detected, however, snow cover hampered the detection. A comprehensive survey by DRHin May 1996 found a 10 meter square area containing several hot spots of contamination. In June1996, DRH excavated the contaminated soil and debris and, in cooperation with the U.S. EPA,shipped the soil and debris to a disposal facility in Utah. Soil sampling after the excavation foundresidual radium-226 levels of less than 5 pCi/g above background, and DRH declared the site tobe radiologically clean and released for unrestricted use (24, 25, 26, 27).
In July and November 1995, DRH and U.S. EPA staff conducted radiation surveys at a house inthe Bear Lake area that the owners of the Bear Lake site rented after they were relocated fromthe site. The surveys found that some objects at the house were contaminated, probably materialthat the owners had removed from the Bear Lake site when they were relocated. The objectsprobably had not been screened for contamination by the DRH or U.S. EPA. The contaminatedobjects were either decontaminated or confiscated for proper disposal (3, 15, 22).
Surface water samples collected from Bear Lake and well water samples collected from wells onproperties adjacent to the Bear Lake site contained less than 0.2 pCi/L radium, considered withinnormal background ranges (8, 19).
On October 9, 1996, MDEQ-DWRP personnel collected 8 sediment samples from the Paw PawRiver and 6 soil samples from the bank of the river in the same locations. Seven of the sedimentsamples and 5 of the soil samples were collected near the Benton Harbor site. One sediment andone riverbank soil sample were collected approximately 0.5 miles upstream for backgroundvalues. The sediment samples near the site contained up to 1.7 ± 0.8 pCi/g radium-226, theriverbank samples near the site contained up to 0.6 ± 0.6 pCi/g radium-226. The backgroundsediment sample contained less than 0.7 pCi/g radium-226, the background riverbank samplecontained 1.0 ± 0.7 pCi/g radium 226 (28).
In preparing this public health assessment, the MDCH relied on the information provided in thereferenced documents and assumed that adequate quality assurance and quality control measureswere followed with regards to chain-of-custody, laboratory procedures, and data reporting. Thevalidity of the analysis and conclusions drawn for this Health Assessment is determined by thereliability of the referenced information.
Several of the buildings on the Benton Harbor site are dilapidated and in various states ofcollapse. Trespassers and remedial workers on the property might be injured if one of thesebuildings collapses while they are inside it. The site has recently been partially fenced, thoughthree sides of the perimeter are not fenced. Crates inside the H & K Sales warehouse in Beldingwere labeled as containing unexploded ammunition, though examination of some of the crates hasnot found any ammunition. If live ammunition is present, a fire on the site would pose a danger ofexplosion.
To determine whether nearby residents are exposed to contaminants migrating from sites ofcontamination, ATSDR evaluates the environmental and human components that lead to humanexposure. An exposure pathway contains five major elements: a source of contamination,transport through an environmental medium, a point of exposure, a route of human exposure, andan exposed population.
An exposure pathway is considered a completed pathway if there is evidence that all five of theseelements are or have in the past been present. A pathway is considered a potential pathway if oneor more of these elements is not known to be or have been present, but could be or have been. An exposure pathway can be eliminated from consideration if one of the elements is not presentand could never be present. The following sections discuss the most important exposurepathways at the Michigan Sites of Radium Dial Contamination.
Employees of Aircraft Components and workers at the D & L Sales and H & K Sales warehouseshave breathed air containing elevated concentrations of radon and possibly airborne particulatematter containing radium. The workers have also been exposed to alpha, beta, and gammaradiation from the instruments. The worker population at these warehouses totaledapproximately 40 (10). DRH and the U.S. EPA have advised the current owners and occupantsof the two warehouses against any occupancy of the areas of the buildings where radioactivematerials have been found. The agencies have also advised the owners that no material should be removed from the warehouses without screening to verify that the material is not contaminated.
Trespassers on the two warehouse sites might also be exposed to the radioactivity and associatedradiation present on the site. The Benton Harbor site was partially fenced in July 1995, blockingaccess from the most accessible side, along North Shore Road. In addition, major areas ofcontaminated soil were completely fenced and hazard warning signs were posted. Pedestriansmay still obtain access to the site through the unfenced north, east, and south (riverbank) sides ofthe property (3).
In early 1994, the Belding warehouse was posted with "Caution -- Radioactive Material" signs. Passages connecting the contaminated and uncontaminated areas of the buildings on the propertyhave been blocked. The contaminated areas of the Belding site were fenced off from theuncontaminated portions of the property in late 1995. The tenants who were using other portionsof the Belding property have allowed their leases to expire and have vacated the property.
Residents at the Bear Lake site have breathed air containing elevated concentrations of radon andairborne radium particulates. They have also been exposed to alpha, beta, and gamma radiationfrom the instruments. Instrument repair, refurbishment, and calibration at the Bear Lake sitegenerated radium-containing dust. Any individuals performing this work without appropriatesafeguards were exposed to this dust, and radioactive dust was found throughout the house inwhich the work was done. All residents and visitors to the house were probably exposed to thedust. Five people continually lived in the house for many years. Counting regular visitors to thehouse, the total exposed population at the Bear Lake site might be 18 to 20 (8). The house on thesite has been demolished and all contaminated material removed for proper disposal. Preliminarypost-clean-up sample results indicate that the site can now be released for unrestricted use.
At the Bear Lake and Benton Harbor sites, material contaminated with radium has been found inthe outdoors environment in limited areas (2, 4). A floor drain in a basement at the BentonHarbor site probably leads directly into the soil or to the nearby Paw Paw River. The drain itselfand the floor around it show elevated radiation levels (16). Soluble radium compounds might beleached into the groundwater. Soil contaminated with radium might be transported by surfacerunoff to nearby surface water bodies (Bear Lake and the Paw Paw River, respectively), wheresoluble radium compounds might contaminate the water and insoluble compounds might settleinto the sediment. People using the groundwater for household water supply or using the surfacewater bodies for recreation might thereby be exposed to the contamination in the water orsediment. At Bear Lake, no contamination was found in surface soil between the contaminatedareas and the surface water bodies, indicating that transportation of contaminants by surfacerunoff has been minimal. A preliminary survey of riverbank soil and sediment near the BentonHarbor site found no radium-226 significantly above background values (28).
Contaminated soil from the Bear Lake site and adjacent property were removed for disposalelsewhere by the U.S. EPA, and the properties declared free for unrestricted use. The migrationof radium from the house at the Bear Lake site to the surrounding soil appears to have beenprimarily through the air or on the bodies and clothes of the residents and visitors. Groundwaterfrom private wells near the Bear Lake site and the surface water of Bear Lake have been testedand only background levels of radium were found (8).
There is no record of sampling of water from the Paw Paw River or of groundwater near theBenton Harbor site. The Benton Harbor municipal water system uses surface water from LakeMichigan. Groundwater at the Benton Harbor site probably discharges to the Paw Paw River andany contamination in the groundwater would not be found beyond the site boundaries. Theclosest residences to the site are served by the Benton Harbor municipal water system. Thenearest residences where private wells are in use are located northwest of the site, and probably upgradient to groundwater flow from the site.
In the case of a fire on the Benton Harbor or Belding sites that reaches the gauges, radium-contaminated material might be volatilized and transported downwind through the air. The ashfrom the fire might also contain radioactive material. Wind could then spread radioactive ash intodownwind areas. Anyone outdoors in the downwind area during and after the fire might beexposed to radioactive material. Belding fire, police, and emergency medical personnel haveexpressed concerns about the potential danger of the spread of radiological contamination shoulda fire occur in the H & K warehouse. The U.S. EPA has held training sessions for Beldingemergency response personnel regarding the appropriate response to a fire on the site. MDPH/MDEQ, the U.S. EPA, and Benton Harbor and Belding officials have developedemergency contingency plans for the sites in the case of a fire or other natural disaster.
The primary benchmarks against which exposures are evaluated for their potential for causingnon-cancer adverse health effects are the Minimal Risk Levels (MRLs), developed by ATSDR,and Reference Doses (RfDs) and Reference Concentrations (RfCs), developed by the U.S. EPA. It is generally accepted that a person exposed to a dose of a chemical less than an MRL, RfD, orRfC is not likely to experience non-cancer adverse health effects. The derivation of MRLs, RfDs,and RfCs from the observed threshold exposures includes safety factors to allow for differentresponses between species and between individuals. However, these values may not be protectivefor individuals who are hypersensitive to chemical exposures, including the very young, the veryold, individuals whose bodies are under stress from illness, and individuals who have an allergicresponse to the chemical.
Threshold exposures from which MRLs, RfDs, and RfCs are derived may also be cited if none ofthe derived values are available. The threshold exposures include Lowest Observed AdverseEffect Levels (LOAELs) and No Observed Adverse Effect Levels (NOAELs). In a givenexperiment, with exposure route, species, and health effect specified, the LOAEL is the lowestexposure at which the effect was observed, and the NOAEL is the highest exposure at which noeffect was observed.
For chemicals which may cause cancer, the risk associated with an exposure is evaluatedseparately from non-cancer health risks, using published potency factors, which relate the chanceof contracting cancer to the dose of the chemical. For this assessment, the risk of cancer isconsidered significant if 1 extra case of cancer is likely to develop among 1,000,000 peoplesubject to the exposure over their lifetimes.
For this assessment, doses from radiation exposure are computed using the following standardassumptions (29): an adult weighing 70 kilograms (154 pounds) who drinks 2 liters(approximately 2 quarts) of water a day and incidentally ingests 100 milligrams of soil per day; achild weighing 10 kilograms (22 pounds) who drinks 1 liter (approximately 1 quart) of water perday and incidentally ingests 200 milligrams of soil per day, or, if subject to pica behavior,deliberately ingests 5,000 milligrams of soil per day. Pica behavior is an abnormal urge toconsume non-food substances, such as soil, that most commonly occurs between ages 2 and 5. To provide a conservative assessment of potential health risks, the doses are calculated from the maximum reported concentrations of the contaminants in each medium.
There are no MRLs, RfDs or cancer slope factors available for radium. The literature describesdoses in terms of the total radium ingested. No one would be likely to ingest enough radium fromthe soil on any of these sites to attain the dose at which adverse non-cancer health effects havebeen observed. Children of the age subject to pica behavior are not likely to be on the BentonHarbor or Belding sites. An adult would not be likely to incidentally ingest enough radium fromthe soil at the D & L Sales warehouse site to exceed the lowest dose at which cancer wasobserved in epidemiological studies of workers who applied radium-containing luminous paint toaircraft instrument dials.(5) A pica child living for 3 years in the residence on the Bear Lake sitemight have ingested enough radium from the soil in the back yard to equal that dose. No otherindividual is likely to have incidentally ingested enough radium from the soil at the Bear Lake siteto equal that dose (30). The contaminated soils from the Bear Lake site have been removed, andfuture exposure will not occur.
There are no MRLs, RfDs, RfCs, or cancer slope factors available for radon. The concentrationsof radon found in the air in the buildings on all three sites exceeded the concentrations at whichincreased rates of lung cancer have been observed in epidemiological studies of people who wereexposed to high radon levels in their residences or their employment for many years(6) (31).
Using a slope factor for cancer risk from radiation also used by the U.S. EPA and the NuclearRegulatory Commission (32), all residents of the Bear Lake site have incurred a greatly increasedrisk of contracting cancer from the radiation throughout the house.
Based on all available data from the three sites, the owner of the Bear Lake site, who alsoperformed the gauge refurbishment work, most likely received the highest dose of radiation due to his prolonged (at least 20 years) exposure to radioactive material, both external and internal (through inhaled dust and radon).
The former Aircraft Components, Inc. workers that MDPH staff interviewed reported a widevariety of health problems, including arthritis (attributed to age), severe or migraine headaches,and benign ovarian cysts. No single health problem was cited by more than two workers. Theproblems cited are not known to be radiation-related, and there is no pattern to connect theproblems to the subjects' work history.
MDCH has obtained copies of the death certificates for a co-owner of and two former workersfor Aircraft Components, Inc. who died between 1986 and 1993 at over 70 years of age. Thecauses of their deaths were not clearly radiation-related. It had been reported to MDCH that oneworker had died of bone cancer, but the death certificate said the cause of death was lung cancer. Either lung or bone cancer could be radiogenic. Another co-owner of Aircraft Components, Inc.reportedly committed suicide, but the death certificate was not available (13, 33).
MDPH-DRH/MDEQ-DWRP and other agency personnel replied to the concerns voiced by themembers of the public around the sites. Most concerns expressed related to their potential forexposure to the contaminants. Some citizens asked about the potential health effects resultingfrom exposure to the contaminants, and the agency personnel provided information from theliterature (such as References 30 and 31) and their professional expertise and experience toanswer their questions.
The U.S. EPA relayed concerns from a former Aircraft Components, Inc. employee, who is nolonger living in the area, to MDEQ-DWRP, who advised her to consult with her personalphysician. MDEQ-DWRP also offered to consult with her physician to answer any additionalquestions. MDEQ-DWRP is working with the U.S. EPA to arrange a radiation scan at a facilitythat is more convenient to her current residence (14).
U.S. EPA personnel have inspected some boxes in the Belding warehouse which were labeled ascontaining ordnance, and found no ordnance in them. However, the entire contents of thewarehouse have not been inspected, because of physical constraints on doing so. When theradioactive materials are removed from the warehouse, all boxes will be inspected and anyunexploded ordnance disposed of properly (34).
MDPH staff collected water samples from private wells on and around the Bear Lake site in July1995, found radium concentrations within the typical range, and relayed the findings to theowners, concluding that there was no evidence of exposure to radium by that route.
The MDCH released a draft of this Public Health Assessment for public comment on January 22,1997. The comment period lasted until February 21, 1997. No comments from the public werereceived by MDCH in this period.