Inhaling, toxic chemical

Box 3.8 LCt5o values for some inhaled toxic chemical agents... 

P. G. Watanabe, D. G. Pegg, J. D. Burek, H. O. Yakel, and L. W. Rampy, M 90-Day Bepeated Inhalation Toxicity Study of Cumene Hydroperoxide in Bats, Toxicology Research Laboratory, EPA Document No. 868600016, Eiche No. OTS0510168, Dow Chemical USA, Midland, Mich., 1979. 

Based on tests with laboratory animals, aniline may cause cancer. The National Cancer Institute (NCI) and the Chemical Industry Institute of Toxicology (CUT) conducted lifetime rodent feeding studies, and both studies found tumors of the spleen at high dosage (100 —300 mg/kg pet day of aniline chloride). CUT found no tumors at the 10—30 mg/kg per day feeding rates. The latter value is equivalent to a human 8-h inhalation level of 17—50 ppm aniline vapor. In a short term (10-d) inhalation toxicity test by Du Pont, a no-effect level of 17 ppm aniline vapor was found for rats. At high levels (47—87 ppm), there were blood-related effects which were largely reversible within a 13-d recovery period (70). 

Isocyanates. Isocyanates in general are toxic chemicals and require great care in handling. Oral ingestion of substantial quantities of isocyanates can be tolerated by the human body, but acute symptoms may develop from the inhalation of much smaller amounts. The inhalation of isocyanates presents a ha2ard for the people who work with them as weU as the people who Hve in the proximity of an isocyanate plant. Adequate control of exposure is necessary to achieve a safe working environment. The suppHers Material Safety Data Sheets (MSDS) have to be consulted for the most current information on the safe handling of isocyanates. 

Toxic chemicals can enter the body in various ways, in particular by swallowing, inhalation and skin absorption. Skin absorption may lead to dermatitis and this can be a most annoying complaint. Whereas some chemicals may have an almost universal effect on human beings, others may attack only a few persons. A person who has worked with a given chemical for some years may suddenly become sensitised to it and from then on be unable to withstand the slightest trace of that material in the atmosphere. He may as a result also be sensitised not only to the specific chemical that caused the initial trouble but to a host of related products. Unfortunately a number of chemicals used in the plastics industry have a tendency to be dermatitic, including certain halogenated aromatic materials, formaldehyde and aliphatic amines. 

Edema Edema is an abnormal accumulation of body fluid in tissues. An edema can be as trivial as a blister on your thumb, as life-threatening as a constriction of your airway. As in real estate, the three factors that determine the dangers associated with an edema are location, location, location. Exposure to toxic chemicals can cause a variety of edemas. Pulmonary edema (fluid in the lungs) is particularly dangerous, if not treated. Be sure to avoid inhalation of chemicals whenever possible and to use proper protective measures, as suggested on the MSDS (fume hoods, respirators, etc.). 

Inhalation is the most rapid route, immediately introducing toxic chemicals to respiratory tissues and the bloodstream. Once admitted to the blood through the lungs, these chemicals are quickly transported throughout the body to contact all organs. In many cases, chemicals accumulate in a target organ. 

Toxicity is defined as the quality, state, or degree of being toxic or poisonous. Some liquids contain chemicals that are a serious toxic hazard. These toxic or poisonous chemicals may enter the body through inhalation, by absorption through the skin, or through the eyes or the mouth. The result is sickness and, in some cases, death. Manufacturers of hydraulic liquids strive to produce suitable liquids that contain no toxic chemicals and, as a result, most hydraulic liquids are free of harmful chemicals. Some fire-resistant liquids are toxic, and suitable protection and care in handling must be provided. 

False. When someone smokes tobacco, the air becomes contaminated with tobacco smoke over a wide area. This can be particularly dense when several people smoke in the same room. This smoke contains high levels of toxic chemicals and can eventually lead to all of the diseases associated with smoking, even in non-smokers who inhale it. 

CIIT. 1983a. 90-Day vapor inhalation toxicity study of hydrogen sulfide in B6C3Fj mice. Report to the Chemical Industry Institute of Toxicology, Research Triangle Park, NC, by ToxiGenics, Inc. CUT docket 42063. 

Comstock, C.C., and F.W.Oberst. 1952. Inhalation toxicity of aniline, furfuryl alcohol and their mixtures in rats and mice. Medical Laboratories Research Report 139, Chemical Corps Medical Laboratories, Army Chemical Center. 

RichardW. Purgh, Quantitative Evaluation of Inhalation Toxicity Hazards," in Proceedings of the 29th Loss Prevention Symposium (American Institute of Chemical Engineers, July 31,1995). 

Use Joseph F. Louvar and B. Diane Louvar, Health and Environmental Risk Analysis Fundamentals with Applications (Upper Saddle River, NJ Prentice Hall, 1998), pp. 287-288, to find the toxicity levels (high, medium, low) for the inhalation of toxic chemicals. 2-29. Use Louvar and Louvar, Health and Environmental Risk Analysis, pp. 287-288, to find the toxicity levels (high, medium, low) for the single dose of a chemical that causes 50% deaths. 

Conclusion Toxicity data are available for many thousands of solid, liquid, and gaseous chemicals and other materials. The data for inhalation toxicity provide guidance for concentration and duration limits, for protection of the public, chemical plant employees, and emergency response personnel. Similar data for ingestion and skin contact with toxic materials are not as readily available. Investigation into toxic effects is continuing, so that toxic materials can be handled safely. 

Hext, P.M. 1989. 90-day inhalation toxicity study in the rat. ICI Report No. CTL/P/2466. Central Toxicology Laboratory, Imperial Chemical Industries, Alderley Park, Macclesfield, Cheshire, U.K. (Cited in NRC 1996). 

Hino, Y, K.Yamasaki, and K.Schiraishi. 1992. Twenty-eight-day repeated inhalation toxicity study of HCFC 141b in rats. Report B 18-0005, Hita Research Laboratory Chemical Biotesting Center, Chemicals Inspection and Testing Institute, Japan. 

However, if you link the hydroxyl group with the methane molecule rather than the ethane, you get the potentially toxic chemical called methyl alcohol, or wood spirit. Similarly, if you add what s called an aldehyde group (-CHO) instead of the hydroxyl group, you will get one of a variety of chemicals called aldehydes, of which a common one is the gas formaldehyde (HCHO), widely used in the manufacture of plastics and glues. This gas can be an irritant and potentially dangerous if inhaled. 

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