Toxicity of Military Smokes and Obscurants Volume 1 (1997) / Chapter Skim
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5 - Hexachloroethane Smoke
5 - Hexachloroethane Smoke
Pages 127-160
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From page 127... ...
Therefore, the exposure response assessments for HC smoke are probably most reliably interpreted, given present ciata, on the basis of the echo sure response data for ZnCI2. 11n this chapter, HCE refers to the compound hexachloroethane, and HC smoke is the term used by the military for smoke produced by combusting HCE with zinc oxide and producing zinc chloride.
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From page 128... ...
HC smoke is produced by burning a mixture containing roughly equal parts of HCE and ZnO and approximately 6% granular aluminum. Combustion Products The smoke mixture in a smoke bomb or grenade is initially ignited by a pyrotechnic starter mixture.
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From page 130... ...
The cadmium and lead con centrations ctispiayed a strong negative correlation. Trace gas phase products were measured in a field test of a standard M5 HCE 30 ib smoke pot (Katz et al.
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From page 131... ...
Relative humidity had no consis tent effect on the total particulate concentration or the particle size. As the aerosols aged over a 2 hr period, the mass median and count mean diameters nearly doubled as the particle concen tration decreased by a factor of about 6.
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From page 133... ...
(1989) collected air samples during ~ hr demonstrations of M5 smoke pots and M8 smoke are nacles at the U.S.
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From page 134... ...
A computer simulation of exposure to smoke released from 41 M5 smoke pots was carried out for a winct speect of 6 m/see using the HAZARD2 program (Cichowicz 1983~. The roughly rectangular area with exposures expected to exceec!
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From page 136... ...
1987~. The smoke generator squads must stay 50 to 75 m directly downwind of the smoke pots.
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The most significant possible exposure is to HCE. HCE is a white crystalline solid with a vapor pressure equivalent to 770 ppm at 25°C (Eaton et al.
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From page 138... ...
Inhalation Exposures One-Time Exposures All the effects of human exposure to HC smoke are attributed to the ZnCI2 component of the smoke.
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From page 139... ...
Pu/monary Effects. Pulmonary effects include clyspnea, chest constriction, retrosternal and epigastric pain, hoarseness, cough, lacrimation, expectoration, anc!
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From page 140... ...
When applied to the shaved skin of guinea pigs, weight loss was evident. In rabbits, severe erythema was noted both on abradecl and unabraded skin, and eye application induced severe corneal clamage, an effect manifest 4 clays to 2 weeks after applica lion (ATSDR 1994~.
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From page 141... ...
Repeated Exposures [etha/i~ and Pulmonary Effects. Marrs et al.
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From page 142... ...
Inflammatory changes, such as edema, emphysema, and macrophage infiltration in the lungs of rats and guinea pigs, also occurred at the highest exposure concen "ration. The middle and tow exposure groups exhibited normal survival rates, and no Diverse pulmonary effects were evident.
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144 o o no v 4 U3 o o 4 o z 54 ~ v u, ~1 1 ~ o ~ U3 of ~ o .= ~ o C`: ~ c)
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145 Do Cal 4~ U)
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downwind of a smoke pot might result in exposure concentrations of 2,000 mg~min/m3 or higher, which could result in the need for hospitalization ant! treatment (see Table 5 5~.
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1988) , the subcommittee clecided to estimate the po tential carcinogenic potency of HC smoke based on this study as a screen to determine whether further analysis is warranted.
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would be 0.086 mglkg of body weight per clay (i.e., the potency of total HC smoke of 0.036 mg/kg per day divicled by 0.42~. Cancer potency based on scaling body weight to the 3/4 power woulc!
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From page 149... ...
= 0.0049 mg/kg per day. Uncler "very stable" atmospheric conditions, the exposure concen "rations from a single smoke pot is 9,900 mg~min/m3, resulting in an average ciaily lifetime dose of 0.044 mg/kg per day for a smoke pot operator.
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From page 150... ...
If average atmospheric conditions are assumed, the estimated risks for smoke pot operators would be lower. In the community of Baker, even using the unrealistic worst case atmospheric conditions, the average daily lifetime dose was estimated to be 1 x 10 6 mg/kg per day, resulting in a lifetime can cer risk of less than 3.6 x 10 8 (i.e., 0.036 x 10 6)
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From page 151... ...
exposure guidance levels for military personnel exposed during an emergency release or cluring regular training exercises and for nearby communities to protect them from emergency or repeated releases of HC smoke. Military Exposures Emergency Exposure Guidance Level (EEGL)
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From page 152... ...
Comparison with Other Exposure Guidance Levels The ACG1H 8 hr TEVIWA for ZnCl2 of I.0 mg/m3 is higher than both the 6 hr EEGL of 0.4 and the PEGL of 0.2 mg/m3 recommended above. The ACGTH TL~V TWA is based on 3Guidance for repeated exposure of military personnel during training exercises.
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From page 153... ...
. Assuming further an inhalation rate of 0.03 m3/min, the exposure concentration generated by the smoke pot couici not exceed 630 mg~min/m3 (i.e., 19 mg divided by 0.03 m3/min)
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anti estimated the corresponding cancer risk associated with the recommencled exposure guidance levels for military personnel ant! the public.
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Summary of Subcommittee Recommendations Table 5 8 summarizes the subcommittee's recommendations for EEGEs and the PEGL for military personnel exposed to HC smoke. Table 5 9 summarizes the subcommittee's recommencia lions for SPEGEs and the PPEGL for military training facilities to ensure that nearby communities are not exposed at concentrations that might cause Diverse effects.
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From page 156... ...
If use of HC smoke crevices based on reac lions of HCE with ZnO continues, then aciclitional information with respect to effects on other organs and systems is required to ensure the health of military personnel and to prevent releases beyond military facilities that might pose risks to the general pub lic. REFERENCES ACGIH (American Conference of Governmental Inclustrial Hyglenists)
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From page 157... ...
1990. The histo pathology of rat lung following exposure to zinc oxicle/hexachioro ethane smoke or instillation with zinc chloride followed by treat ment with 70% oxygen.
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From page 158... ...
1976. A Risk Analysis of Exposure to High Concentrations of Zinc Chloride Smoke.
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From page 159... ...
1989. Fielci Exposure of Chemical School Students and Cadre to Fog Oil and Hexachioro ethane (HC)
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