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United States Fish and Wildlife Service Buildings at Caddo Lake National Wildlife Refuge



The Texas Department of Health (TDH), in cooperation with the Agency for Toxic Substances and DiseaseRegistry (ATSDR), was asked by the United States Fish and Wildlife Service (USFWS) to evaluate thehuman health significance of sampling data collected from within various buildings at the Caddo LakeNational Wildlife Refuge (NWR). The USFWS buildings are located on the former Longhorn ArmyAmmunition Plant site in Karnack, Harrison County, Texas. The ATSDR and the TDH reviewedenvironmental data for this site and prepared a health consultation in 1996 [1] and a public healthassessment in 1999 [2]. This health consultation specifically evaluates wipe sampling data collected fromwithin the Administration Office, the Fire Station, and the Magazine.

The former Longhorn Army Ammunition Plant site is situated on 8,493 acres and is approximately 14miles northeast of Marshall, Texas [2]. The nearest communities are Karnack (population 775) on thewestern boundary and Uncertain (population 150) to the north [3]. The plant was operated by the UnitedStates government from 1942 to 1945 and then from 1952 until 1997. Production at the plant included2,4,6-trinitrotoluene (TNT), pyrotechnic ammunition, rocket motors, and plastic explosive. The site wasplaced on the U.S. Environmental Protection Agency (EPA)National Priorities List on August 30, 1990 [2].


In January 2003, surface wipe sampling data were collected by USFWS personnel. The samples wereanalyzed for total polychlorinated biphenyls (PCBs), Aroclors(1) [4], and lead.

A total of ten (10) wipe samples(2) were collected from three (3) buildings. Four (4) samples were from theFire Station, three (3) samples from the Magazine, and three (3) samples from the Administration Office(Table 1).

The ATSDR does not have specific health standards for evaluating wipe sampling data. PCB and leadregulatory requirements established by the EPA were used as surrogates since they utilize wipe samplingdata to establish compliance with clean-up standards. Analysis indicated that total PCBs and Aroclorconstituents were in some of the samples. However, all of the levels were below the EPA regulatorycleanup standard of 10 µg/100cm2 for PCBs [5]. Sampling results indicate that lead is a constituent ofconcern because some of the samples contained lead in excess of regulatory clean-up standard of < 40µg/ft2 (or < 4.3 µg/100cm2) [6].

The degree of human health concern is based both upon the level of exposure and the nature of the hazard. The route of exposure for lead would be through incidental ingestion or inhalation of contaminated dustin the buildings. Children tend to absorb lead primarily through ingestion. Absorption of lead by adultsis greater via inhalation rather than via the gastrointestinal tract. Since adults will be the primary occupantsof the buildings, there is a low likelihood that exposure to lead at the USFWS buildings through incidentalingestion of the contaminated dust poses a health hazard.

Inhalation is the route of exposure of potential concern. Time spent by personnel in the AdministrativeOffice and Fire Station is estimated to be 8 to 9 hours per day. The Magazine, which is used strictly forstorage, would be occupied for less than 8 hours a day [7]. Generally, if lead is airborne, it can be absorbedin far greater quantities through inhalation. The highest reading for lead was from the AdministrationOffice Vent in Room 508. This sample was collected after removing a screen and wiping inside the vent. The second highest reading was collected from a ceiling beam approximately 12 feet above the floor inthe Magazine [8]. These samples suggest that at one time lead was airborne in these areas. From theavailable data, we could not determine if the sample results reflect a historical (when the facility was active) or an on going recirculation of lead through the air.


The primary constituent of concern based on the sampling results is lead. USFWS building occupants areprimarily adults who work in the buildings for up to 9 hours a day. The surface dust sample data reviewedsuggests that at one time lead was airborne. Based on the samples reviewed, the TDH/ATSDR was notable to determine whether the lead is the result of historical deposition or current recirculation. Thus,TDH/ATSDR could not determine if occupants in the USFWS Administration Office and the Magazineare currently being exposed to lead at levels of concern through inhalation. TDH/ATSDR concludes thatthe presence of lead in the buildings poses an indeterminate public health hazard.


Actions Taken

  1. A health consultation was completed for the Longhorn Army Ammunition Plant on April 26th, 1996.

  2. A public health assessment was completed for the Longhorn Army Ammunition Plant on July 9th, 1999.

Actions Recommended

  1. Thoroughly clean areas in which laboratory analyses indicated the presence of lead.

  2. Collect air samples in the Administration Office and Magazine and analyze for lead.

Actions Planned

  1. TDH/ATSDR will evaluate the public health significance of the air sampling results when they become available.


  1. Agency for Toxic Substances and Disease Registry. Health Consultation for Longhorn Army Ammunition Plant. Karnack, Harrison County, Texas. CERCLIS No. TX6213820529. U.S. Department of Health and Human Services. April 26, 1996.

  2. Agency for Toxic Substances and Disease Registry. Public Health Assessment for Longhorn Army Ammunition Plant. Karnack, Harrison County, Texas. CERCLIS No. TX6213820529. U.S. Department of Health and Human Services. July 9, 1999.

  3. U.S. Census Bureau website. American Fact Finder Census 2000. February 2003.

  4. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polychlorinated Biphenyls (update). November 2000.

  5. Title 40. Code of Federal Regulations. Part 761. Polychlorinated Biphenyls (PCBs)Manufacturing, Processing, Distribution in Commerce, and Use Prohibitions. July 1, 2001.

  6. Title 40. Code of Federal Regulations. Part 745. Lead; Identification of Dangerous Levels of Lead; Final Rule. January 5, 2001.

  7. Memorandum. USFWS Ecological Services to USFWS EPA Liaison. Surface Wipe Samplingin Structures at Caddo Lake National Wildlife Refuge. February 2003.

  8. Personal Communication. Tom Ellerbee, Environmental Health Specialist, Texas Department of Health with Craig Giggleman, Contaminants Specialist, U.S. Fish & Wildlife Service. February 2003.


Tom Ellerbee
Environmental Health Specialist

John F. Villanacci, Ph.D.
Environmental Epidemiology and Toxicology Division


George Pettigrew, P.E.
Senior Regional Representative
ATSDR - Region 6


Robert B. Knowles, M.S., R.E.H.S.
Environmental Health Scientist
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
State Programs Section


This health consultation was prepared by the Texas Department of Health under a cooperativeagreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordancewith approved methodology and procedures existing at the time the health consultation was initiated.

Robert B. Knowles
Technical Project Officer, SPS, SSAB, DHAC, ATSDR

The Division of Health Assessment and Consultation, ATSDR, has reviewed this
health consultation and concurs with its findings.

Sven E. Rodenbeck
for Roberta Erlwein
Chief, State Programs Section, SSAB, DHAC, ATSDR

Table 1.

Dust Wipe Sample Analysis from United States Fish & Wildlife Buildings
Caddo Lake National Wildlife Refuge (Former Longhorn Army Ammunition Plant)
Location Constituent
  Lead Total PCBs Aroclor 1260* Aroclor 1254 Aroclor 1248 Aroclor 1242 Aroclor 1232 Aroclor 1221 Aroclor 1016
Administration Office - Room 508 - Vent


Magazine - Floor


Magazine - Ceiling Beam


Magazine - North Wall                  
Administration Office - Room 501 - Intake                  
Administration Office - Vault Wall                  
Fire Station - Vent                  
Fire Station - North Wall                  
Fire Station - East Wall                  
Fire Station - West Wall                  

* = Aroclor was a trade name of the Monsanto Corporation for its polychlorinated biphenyl products. The approximate chlorine content is indicated by the last two digits. Thus, Aroclor 1260 has an average chlorine content of 60% by weight. Aroclor 1016 is the exception, as it contains an average chlorine content of 41% by weight [4].

T = Constituent exceeded EPA regulatory standards.

1. Aroclor was a trade name for polychlorinated biphenyl products of the Monsanto Corporation.
2. Samples were collected by wiping a 100 square centimeter area.

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