ABSTRACT
I. Introduction and General Considerations........................................................................... 469 II. Applications of Screening Smokes .................................................................................... 470 III. Smoke Generation .............................................................................................................. 471 IV. Exposure Patterns and General Protective Measures ......................................................... 471 V. Toxicity Assessment and Health-Hazard Evaluation of Screening Smokes...................... 473
A. Laboratory Toxicological Studies............................................................................... 473 1. Inhalation Toxicology Studies ............................................................................. 473 2. Cutaneous Toxicity Studies ................................................................................. 475 3. Ocular Toxicology ............................................................................................... 475 4. Special End-Point Studies.................................................................................... 475
B. Human Volunteer Studies........................................................................................... 476 C. Environmental and Ecotoxicological Considerations................................................. 478
VI. Specific Screening Smoke Materials .................................................................................. 478 A. Phosphorus Smokes .................................................................................................... 478
1. Red Phosphorus Smoke....................................................................................... 478 2. White Phosphorus Smoke.................................................................................... 480
B. Titanium Tetrachloride Smoke ................................................................................... 482 C. Zinc-Hexachloroethane Smoke .................................................................................. 483 D. Diesel-Fuel Smoke...................................................................................................... 486 E. Fog-Oil Smoke............................................................................................................ 487 F. Dye-Based Smokes ..................................................................................................... 488 G. Cinnamic Acid Smoke................................................................................................ 491
VII. Overexposure To Screening Smokes and Its Medical Management ................................. 491 References ..................................................................................................................................... 492
Screening smokes have a major military use in concealment operations by the generation of a foglike atmosphere composed of light-scattering particles that prevent or markedly limit the visibility
of, and actions of, troops or vehicle movements where occult operational characteristics are of tactical importance. As noted in Section II, they are also used for a variety of other military and civilian purposes during which the user and bystanders may be exposed to the smoke; these include various types of training, rescue operations, and fire simulation. Screening smokes are produced by the deliberate burning or vaporization of a material or formulation to form an opaque cloud, and they are often differentiated from obscurants, which are usually defined as naturally occurring particles suspended in air that block or attenuate the transmission of parts of the electromagnetic spectrum, such as visible or infrared radiation or microwaves (NRC, 1997). Examples of obscurants are fog, mist, and dust.
