Toxicity of Military Smokes and Obscurants Volume 2 (1999) / Chapter Skim
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3 Brass Smoke
3 Brass Smoke
Pages 45-67
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Army uses a product called EA 5763 that contains brass flakes. Other products containing brass flakes developed by the military include EA 5763D and EA 5769, but those are not in use.
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Explosion of the grenades simply releases the brass flakes that senre to block detection of infrared waves.
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. However, the effects of chronic exposures to brass fumes from the brass industry in India have been published (Rastogi et al.
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Those studies indicated that long-term exposures (10-17 years) to fumes containing brass can be associated with increased risk of chronic bronchitis, with an odds ratio risk of 2.74.
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No information was found concerning the reproductive or developmental toxicity of a single exposure to brass flakes by the inhalation route. Repeated Exposures [etha/ity.
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Lactate dehydrogenase activity increased in rats exposed once or more than once and did not return to control values until 4 weeks abler exposure. Protein levels in the ravage fluid of mice were much higher after multiple exposures than after a single exposure, but the single exposure did cause about a lO-fold increase in protein content.
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The disruption of implantation, in utero death, reduced maternal and fetal weight, and an increase in unusual defects indicated serious consequences of exposure to brass flakes for the longest exposure period. Thus, there is evidence of developmental toxicity in rats exposed to brass flakes at 100 mg/m3 for 150 min per day during gestation days 6-15.
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that delayed the mating of the males in the dominant lethal mutation study for 4 weeks longer than that of the males exposed for 15 min per day or the controls. The significant increase in resorptions in pregnancies resulted from matings with males exposed for 150 min per day compared with those exposed for 15 min per day and the controls.
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to gauze pads, moistened with saline, which were placed on two abraded and two unabraded rabbit skin sites and covered for 24 hr. The brass caused very slight edema to the unabraded site and slight edema to the abraded site; the edema resolved in both cases after 72 hr.
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Table 3-2 presents data on single inhalation exposures to brass flakes in several species, and Table 3-3 presents data on multiple inhalation exposures to brass flakes in several species, including exposures of humans to brass dust. Noncarcinogenic Effects Acute exposure to high concentrations of brass flakes produces serious pulmonary inflammation and death in several species.
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55 Cat a' a)
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56 au o Cal ._ A)
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57 Cot In E o ._ COL Lid ~ to, ~ Q _..
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58 .§ Lid m Id a)
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was a NOAEL for rats, and that value can be used to calculate guidance levels for a one-time exposure to brass flakes. Multiple exposures to brass flakes significantly increased the toxicity of this material to rats and mice (Thomson et al.
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SUBCOMMITTEE EVALUATION AND RECOMMENDATIONS Using the toxicity information described above, the subcommittee recommended exposure guidance levels for military personnel exposed during an emergency release and during regular training exercises and for consideration at military-facility boundaries to protect nearby communities from emergency or repeated releases of brass flakes. MILITARY EXPOSURES Emergency Exposure Guidance Levels (EEGEs)
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Multiple exposures to brass flakes produce significantly more toxicity in experimental animals than single exposures that have the same cumulative exposure dose. Data are not available on the effects of human exposure to brass flakes; however, humans who were occupationally exposed to high concentrations of brass fumes exhibit an increased risk of chronic bronchitis and other severe respiratory problems.
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Therefore, the subcommittee concludes that the data from the two experimental animal studies provide justification for the use of the human NOAEL value in the derivation of the REGL. PUBLIC EXPOSURES Short-Term Public Emergency Guidance Levels (SPEGEs)
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The subcommittee recommends that the Army~s use of brass flakes be limited to minimize the potential for increasing toxicity with repeated exposures. RESEARCH NEEDS The subcommittee recommends that long-term, chronic inhalation studies in experimental animals be conducted to characterize the precise toxic effects due to chronic exposure.
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Environmental Protection Agency, Health Effects Research Laboratory, Research Triangle Park, N.C., for U.S. Army Medical Bioengineering Research and Development Laboratory, Fort Detrick, Md.
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1982a. Enzymatic and Cytological Changes in Lung Lavage Fluid from Rats Exposed to Inhaled EA 5763 Flakes.
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1990. Comparative evaluation of nose-only versus whole-body inhalation exposures for rats Aerosol characteristics and lung deposition.
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