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Purpose: The purpose of this report is twofold:

1. To identify the historical data upon which the Chemical Stockpile Disposal Program (CSDP) based its current "safe" levels of exposure to chemical warfare agents (CWA) for workers and the general population.
2. To review the data upon which these current "safe" standards are based in light of the the December 1997 National Research Council Report, "Review of Acute Human-Toxicity Estimates for Selected Chemical-Warfare Agents," (NRC Report [DAMD 17-89-C-9086) to determine if these standards provide"...maximum protection to workers, the public and the environment" during the CSDP operations as required in PL 99-145.

• Are the current CWA low-level exposure standards the CSDP deems "safe" for workers and civilians based on the same toxicity data and analysis concerning acute levels that the NRC recently found to be flawed in its December 1997 report?
• If so, what implications do the NRC's conclusions have for the safety of the Army's chemical weapons incineration program?

a) GB Agent: Since the Army is currently processing (burning) chemical agent GB (sarin) at their only operational incinerator in the U.S. in Tooele, Utah, this section will focus primarily on the safe exposure levels relative to this particular agent. A table of additional findings in the 1997 NRC Report for other agents of concern (VX, H) is contained herein.

b) Development of Current Standards: Worker and general population low-level exposure standards currently used by the CSDP can be traced back to the seminal document setting exposure standards (1). We will call this the "McNamara Study" after its primary author. The "McNamara Study" clearly shows that worker and civilian "safe" agent exposure levels are based on acute and lethal dose standards. It says :

"We will establish concentrations that can be tolerated by workers (healthy adults) during working hours without effect. Concentrations below those proposed for workers will also be established to apply to the continuous exposure to the physically heterogeneous population. These levels will be put into perspective by relating them to various dosages expressed by the product of air concentration and time (Ct) that can be expected to produce particular effects (emphasis added) (2)."

It also states:

"There are considerable data on the acute effects of GB...But systematically obtained data on continuous exposure of the general population to low levels of GB do not, and obviously cannot, exist (emphasis added) (3)." "We believe, therefore, that industrial and environmental 'no effect' levels for GB can be developed from existing data (emphasis added) (4)."

The "McNamara Study" continues:

"When known concentrations of toxic materials have existed in the working environment for long periods without harm to workers, a safe concentration has been established by experience. GB operations have not been of this type in the past and occupational GB exposures have been acute or subacute and uncorrelated with air concentration or dose data. Animal date for both acute and chronic exposures and data on human subjects exposed acutely have been discussed in previous sections. From these data, the consequences of chronic exposure to humans must be inferred. No-effect levels for animals continuouly exposed may not apply directly to man (emphasis added) (5)."

The "McNamara Study" contains repeated cautions concerning the lack of information upon which to base "safe" worker and civilian exposure standards. Through no fault of the authors, but rather due to the obvious dearth of credible data, the authors consistently equivocate on specific conclusions. Repeatedly the authors state assumptions made due to the lack of complete or adequate data. Yet, the basis for setting low-level exposure standards on acute data remains clear:

"'No effects' level can only be determined on the basis of existing data (6)."

"Little is known about the pathways of metabolism beyond the fact that GB becomes bound to cholinesterase (ChE) and other proteins (7)."

"Workers have been found to have essentially zero blood ChE levels without any signs or symptoms (8)."

"A careful study of these reports presents more questions than answers, and the significance of this information and its relationship to symptomatic, much less asymtomatic, exposures to GB is very doubtful (emphasis added) (9)."

"Unfortunately, there is no chronic study with the same colony of guinea pigs to verify which, if any of the mathematical models can be applied to this situation (emphasis added) (10)."

"It is impossible to state with certainty whether or not there is a threshold concentration based on dose response curves (11)."

"Predicting long-term effects on the eye from continuous exposure to low concentrations of GB is difficult because chronic exposures have not been studied quantitatively with precision (emphasis added) (12)."

"There is insufficient data to adequately support RBC- ChE long term kinetics."(13) "Lacking evidence to the contrary and lacking a better indicator, the recovery of plasma ChE from inhibition by GB will be used as a measure of general recovery from intoxication (emphasis added) (14)."

In the publication, the authors clearly reference the acute (effect) levels as the primary basis for the "safe" air concentrations to workers and civilians which the Army's current disposal program accepts:

"Although GB is an extremely toxic material, there is a threshold for all effects on people. To avoid build-up of an effective dose...exposures of the general population, including individuals of all ages and in all states of health, must be kept well below that which would not be expected to produce effects in healthy workers (15)."

"Nerve agent GB is one of the most toxic synthetic compounds known to man. The possibility that some of this material will escape into the environmental atmosphere during operations intended to destroy the agent makes it necessary to ascertain air concentrations to which the general population could be exposed on a continuous, indefinite basis without showing any effects that could be attributed to GB (16)."

Clearly then, based on the data available at the time, the air concentrations for "protective" exposures to workers and civilians were extrapolated from acute dosage information. Based on the acute exposure data available, authors concluded:

"It is proposed that the concentration in any area to which the general population has access must not exceed 0.0001 mg/m3 averaged over any 1-hour period or 0.000003 mg/m3 averaged over any 72-hour period. In unmasked workers, this concentration must not exceed 0.001 mg/m3 averaged over any 1-hour period; 0.0003 mg/m3 averaged over any 8-hour period; or 0.0001 mg/m3 (8 hr/day) for an indefinite period (17)."

c) Subsequent Regulations and Standards: Since the "safe" exposure standards set in 1971, there have been numerous documents developed within the military and government health angencies addressing acceptable exposure levels of GB to workers and the public.

In 1982 we see the "McNamara Study" standards cited in the Army's Toxic and Hazardous Materials Agency Report regarding worker exposure levels (18). A Department of The Army Headquarters Report later that year uses the same standards (19). Using the same data, the Department of Health and Human Services (HHS) again makes the link to acute levels being the basis for low-level exposure standards in 1988, stating:

"On the basis of the evidence reviewed, HHS concludes that human health will be adequately protected from exposure to GB vapor at the concentrations shown in Table 1. See Table below) Even long-term exposure to these concentrations would not create any adverse health effects. At these concentrations, no detectable reduction in resistance to organophosphorus pesticides would occur (emphasis added) (20)."

Naturally, controlling exposures in the work place and into the environment is critical to disposal efforts and the degree of control is tied to what is deemed "safe" exposure levels. In 1990, the Army released a document focusing on such controls. Again we find the "McNamara Study" air concentrations used as the basis for such controls. This Army Report (21) contains this table, identical to the standards developed in 1971 and the HHS, both based on acute effects:

This same Table is used repeatedly in Army Safety Documents throughout the decade and remains the standard by which safe exposure standards are set for workers and the public (22, 23, 24, 25). However, questions surrounding Gulf War Illness and the possible link to low-level chemical agent exposures placed the issue of "safe" exposure levels back into question. One of the first reports on this topic, done by the Environmental Committee of the Armed Forces Epidemiological Board in 1996, posed a question very relevant to the one we are asking in this overview: "Are there observable long-term effects associated with exposure to sarin (GB) and mustard at concentrations below that needed to cause acute signs, symptoms, or injury (26)?" This report reiterates many of the same problems noted in the "McNamara Study". The Board stated:

"During vapor exposure studies and unintentional vapor exposures, the first signs and symptoms are usually miosis, rhinorrhea and/or chest tightness. In fact, early studies defined an individual as "exposed" when that person had a least one of these symptoms. Persons in the same area, without any health complaints, were not considered exposed. This is the first of a multitude of u related to the questions at hand. Only those who had clinical signs or symptoms would be studied and documented. Anyone else, even if they were in the same area, would not be considered exposed and would not be examined (emphasis added) (27)."

"As will be described below, there are essentially no controlled human studies in which men were exposed to doses calculated to avoid symptoms and where these men were followed over extended periods of time. Several studies utilized doses that did cause acute symptoms, several unintentional high level exposure investigations, and animal studies can be used to make general suggestions regarding the long-term health risks associated with low-level exposure to GB (emphasis added) (28)."

" While these studies involve humans...and animal studies...they represent reasonable evidence that even small doses (exact level is unknown) may result in EEG changes (emphasis added) (29)."

In the "Discussion" section of this Review, the Board states:

"The long-term effects of limited exposures to sub-clinal doses of GB are unclear, but the data included in this review suggest that health effects would not be detectable." "There is NO scientific data that directly apply to the question at hand, and precious little that indirectly address the fundamental question." (emphasis not added). "Indeed, in most studies, the definition of "exposed" was the presence of clinical effects of any degree." "....the inability to work with a dose level, greatly hinders any risk assessment methodology." (emphasis added). "There is no useful methodology found that could be used to adequately extrapolate to the very low concentrations proposed in the question." The most critical limiting factor in this review was the fact that no reports of studies which examined health effects at sub-clinical doses were found (emphasis added) (30)."

The Board concluded:

"There is no scientific information that directly answers the entire question: Are there observable long-term health effects associated with exposure to Sarin (GB) at concentrations below that needed to cause acute signs, symptoms, or injury? Extrapolation from a variety of sources, not designed to answer this particular question, was utilized (emphasis added) (31)." It is prudent to suggest that further research into the long-term effects of low dose GB exposure (including doses that do not result in acute signs or symptoms) on the EEG of primates be undertaken (32)."

The Board recommended:

"The greatest single problem in answering this question is the absence of information regarding health effects (or the lack thereof) of exposure to low doses of HD and GB. The purpose of research would be to determine what, if any, health effects occur upon exposures of varied length to sub-clinical levels of GB and HD.

"During this review, several papers mentioned the potential that susceptibility to chemical agents may vary among exposed individuals. There may be populations that are more susceptible to chemical agent effects than others, and this may bear further review.

"There are no 'No Observable Effects Levels' (NOELS) established with any degree of confidence for any of the chemical agents. These NOELS would be useful for answering questions related to DESERT STORM, but also for establishing workplace and general population exposure limits for demilitarization efforts (emphasis added). Airborne dispersal of chemical agents appears to be the most likely route of exposure, so whole body inhalation might be first priority (33)."

In spite of the unanswered questions throughout the period since the "McNamara Study" there's been no change in the standards between then and those currently deemed as "safe" for workers and civilians within the CSDP. However, new information questions the status quo.

a) Calculating Method for "Safe" Exposure:

Before reviewing the new information it is important to understand the process by which the existing exposure limits were derived. Air concentrations for occupational limits were calculated, based on data demonstrated herein to have been tied direcly to acute exposure effects. A safety factor for workers was applied to these levels. A further safety factor was then applied for civilians, taking into consideration populations that could be more susceptible to chemical agent effects that others. However, regardless of the safety factors applied, if the data upon which these exposure limits are calculated is invalid, it follows that the resultant "safe" exposure standards are also invalid.

A primary acute standard of measurement is Ct50 representing dose concentrations at which 50% of any group react or show signs of exposure to CWAs. Keeping in mind the statement made by the 1996 report from the Environmental Committee of the Armed Forces Epidemiological Board,

"Airborne dispersal of chemical agents appears to be the most likely route of exposure..",

we will use the Lct50, the inhalation exposure at doses which produce lethality in 50% of any given population and, ECt50, the inhalation exposure at doses causing a defined effect (e.g., incapacitation, severe effects, mild effects, threshold effects) in 50% of any given population.

Sometime in 1995-1996, the Pentagon contracted with the National Academy of Sciences to assess the scientific validity of existing human toxicity estimates for CWA's proposed in the 1994 Report done by the Army's Chemical Defense Equipment Process Action Team (CDEPAT) (34). The NRC was not asked to set new standards, but rather to evaluate the proposed standards in the Army's 1994 Report.

The Subcommittee on Toxicity Values for Selected Nerve and Vesicant Agents of the National Research Council's Committee on Toxicology printed its assessment in December of 1997 (35).

What the NRC report shows is that a majority of Human Toxicity Estimates made by the Army in 1994 should be considered either as an interim value or be lowered. Of particular concern is that most of these estimates had already been lowered from previous estimates by the CDEPAT their 1994 report. Yet, no adjustments have been made in the CSDP's exposure levels for workers, civilians, CWA monitoring systems, Allowable Stack Concentrations (ASC) or their Chemical Stockpile Emergency Preparedness Program (CSEPP).

The following Table identifies existing estimates, revised CDEPAT estimates and the NRC recommendations on these revisions for particular agents of concern within the Army's CSDP:

Human Toxicity Estimates for GB

Human Toxicity Estimates for VX

Human Toxicity Estimates for HD

Note that even those estimates deemed valid have been lowered significantly from the existing estimates. These results demonstrate that the levels currently being used by the Army in their CSDP are considerable higher than would be recommended by CDEPAT and by the NRC.

The NRC Report states:

"The toxicity data that the CDEPAT used to derive its proposed estimates were generated primarily from a data base from the 1930s to the 1960s. The existing human toxicity estimates were based on experiments performed 30-40 years ago using various animal species in often poorly controlled studies with vastly different protocals...the subcommittee recognized that the quality of the relevant toxicity data is marginal...Thus, even though the subcommittee concluded that some of the CDEPAT's proposed estimates are scientifically valid, those conclusions are based on a limited toxicity data base. By current standards of toxicity, the toxicity data base for the agents is inadequate, and such inadequacy is a major obstacle to the Army in developing human toxicity estimates with statistical confidence and in developing risk-management strategies (emphasis added) (36)."

The NRC also stated:

"Following a detailed analysis of the toxicity of these agents and using contemporary methods of analysis, CDEPAT concluded that many of the human toxicity estimates in use would not protect the soldier adequately. Recalculations of the potencies of several of the CW agents indicate that their potencies are greater that previously determined, As a result, lower exposure levels of CW agents are expected to elicit adverse effects (emphasis added) (37)."

The implications of these findings are obvious concerning the protection of our troops in battle. It should also be obvious, that these findings have serious implications concerning worker and civilian exposure levels currently deemed "safe" within the Army's CSDP.

Conclusions

1) Acute / Low-level Connection:

The "safe" exposure levels to workers and the public used within the CSDP are based on questionable, inadequate and antiquated studies directly linked to "acute" or "effects" data and are invalid.

This information creates serious questions and severely undermines the validity of :

• the Army's Time Weighted Average (TWA) "safe" exposure levels for workers; the General Population Limits (GPL) for "safe" exposure levels; the adequacy of the monitoring systems deployed within the CSDP; the Allowable Stack Concentrations (ASC) currently used within the CSDP; the Army's CSDP Environmental Impact Statements (both Programmatic and Site specific); the Army's Quantatiative and Human Health Risk Assessments; and,
• the adequacy of the Chemical Stockpile Emergency Preparedness Program (CSEPP).

Status: The Army's prefered technology for disposal of CWA, incineration, is an open-ended approach which, even under ideal operating conditions, releases low-levels CWA into the environment. Since operations began using this technology there have been numerous documented releases of CWA into the environment. Using this technology, determined to be prefered in 1982, the CSDP is currently thirteen years behind schedule and $14.1 Billion over budget. Technology has advanced since 1982. The CSDP is currently being challenged in six legal actions brought by citizens in communities where incinerators are either operating or being constructed.

The seven major systems and their status at the Utah Incinerator (TOCDF) are:

• Liquid Incinerators: Inoperable a large part of the time (> 50%).
  Status: <50% operational at 50% permitted usage rate. Questionable full scale. Metal Parts Furnace: Continuing problems including major incident 1st Qtr. '98.
  Status: Semi-operational at 50% permitted usage rate. Questionable full scale. Deactivation Furnace: Failed M-55 Trial Burn; both TSCA & Utah DEQ. No Rockets processed since 3/97.
  Status: Down Temporarily. Must re-do all Trial Burns. Dunnage Incinerator: Aborted, will never operate.
  Status: Down Permanently. Ventilation System: Continuing problems--high rate of alarms, agent breakthroughs in carbon filters, vestibule problems, seals, etc.
  Status: Semi-operational at 50% permitted usage rate. Questionable full scale. Brine Reduction Area: Shut down permanently as of July 28, 1998. Workforce laid off.
  Status: Down Permanently.
• Pollution Abatement System: Major problems--corrosion of piping, emission flow temperature control, etc.
  Status: Semi-operational at 50% permitted usage rate. Questionable full scale.

Recommendations: The Army must abandon the incineration technology and deploy "closed- looped" disposal technologies (ie: technologies which contain all CWA and their destruction by- products until the residuals can be certified as safe for reintroduction to the environment) in the interest of protecting the health and well-being of U.S. citizens and adherance to PL 99- 145.

Footnotes

1. McNamara BP, Leitnaker, F. "Toxicological Basis for Controlling Emisson of GB into the Environment" EASP 100-98 (1971).
2. Ibid. p. 4.
3. Ibid.
4. Ibid. p. 9.
5. Ibid. p.18.
6. Ibid. p 10.
7. Ibid.
8. Ibid. p.12.
9. Ibid. p. 17.
10. Ibid. p. 24.
11. Ibid. p. 26.
12. Ibid. p. 27.
13. Ibid. p. 28.
14. Ibid. p. 29.
15. Ibid. p. 5.
16. Ibid. p. 9.
17. Ibid. p. 31.
18. McKinney A.L. Estimated Toxicity of Neutralized Salts With and Withhout Trace Amounts of Agent GB DAA-G29-81-D-0100. 1982. p. 16. 19. U.S. Army. Special Occupational Safety and Health Standard for the Evaluation and Control of Occupational Exposure to Agent GB, Pamphlet 40-8. 1982. pgs. 2-1, 2-2, 2-5, B-1, C-1, C-2.
20. Anderson, L.W. Final Recommendations for Protecting the Health and Safety against Potential Adverse Effects of Long-Term Exposure to Low Doses of Agents: GA, BV, VX, Mustard Agent (H, HD, Y) and Lewisite (L). Department of Health and Human Services, Centers for Disease Control Public Health Service, National Center for Environmental Health. 1988. p. 5.
21. U.S. Army. Occupational Health Guidelines for the Evaluation and Control of Occupational Exposure to Nerve Agents GA, GB, GD, and VX Pamphlet 40-8. 1990. p. 5.
22. U.S. Army. Toxic Chemical Safety Standards, DA-PAM 385-61. 1992.
23. U.S. Army ; Army Toxic Chemical Agent Safety Program, AR 385-61. 1992.
24. Memorandum; From U.S. Army Administrative Contracting Office and TOCDF Contractor Memo # RC6537 PM-4470. 1994.
25. U.S. Army; Draft LQCPP, Table 6-5 , Revision 5, Section 6, pgs. 6-24. 1996.
26. Perrotta, DM.; Long-term Health Effects Associated with Sub-clinical Exposuress to GB and Mustard: A Review Conducted by the Environmental Committee/Armed Forces Epidemiological Board. 1996.
27. Ibid. p. 3.
28. Ibid. p. 4..
29. Ibid. p. 6.
30. Ibid. p. 11.
31. Ibid. p. 6.
32. Ibid. p. 7.
33. Ibid. p. 13.
34. CDEPAT (Chemical Defense Equipment Process Action Team), U.S. Army. Review of Existing Toxicity Data and Human Estimates for Selected Chemical Agents and Recommended Human Toxicity Estimates Appropriate for Defending the Soilder. Report No. ERDEC-5P-018. 1994. Classified Report.
35. NRC, Review of Acute Human-Toxicity Estimates for Selected Chemical-Warfare Agents. DAMD 17-89-C-9086. 1997.
36. Ibid. p. 3.
37. Ibid. p. 17.