Accidental exposure to chemicals

According to the European legislation on chemicals at work, employers must assess the risks of chemical hazards to the safety and health of workers, considering effects due to both accidental and long-term average exposures (European Council, 1998). We will here focus on the assessment of accidental task exposure, and a variation of JSA may be used for this purpose  

1 Establish an inventory of all hazardous chemicals that are in use or are planned for use. 

2 For each chemical, determine the potential health effects of being exposed, i.e. the toxicity of the chemical and severity of the consequences. Consult the Safety data sheet. 

3 List all activities that are associated with each chemical and where there is a potential for significant exposure with detrimental health effects through inhalation and/or skin contact. Include activities during handling/ transportation, storage, use, and waste disposal. 

4 For each activity and chemical, estimate the degree of accidental exposure. The extent, frequency and duration of exposures should be taken into consideration. Use the record sheet according to Table 23.1 to document the results. 

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The climate in which the questionnaire was used might raise concern about interpretation of the results. For example, subjects who wished (for whatever reason) to misrepresent the nature and severity of their problems could distort the results (and hence their interpretation), especially if their chemical-test group was fairly small. In addition, as in any cohort study, there was no control of the subjects environments after discharge from the service, so even legitimate complaints associated with exposure to toxic substances could have been due to occupational or accidental exposure to chemical agents, rather than to exposure at Edgewood. 

Another problem with a retrospective study is that the latent period between exposure and the disease (especially when it is cancer) may be long, and so it can be very difficult to make associations between cause and effect. Furthermore, unlike highly controlled animal studies, human exposure to environmental and industrial chemicals is often chronic and may be intermittent, either being completely random or occurring only during the working day. This makes estimation of true exposures more difficult. Accidental exposure to chemicals, both acute and chronic is, for obvious reasons, normally analysed retrospectively, hence any chance to measure exposure levels is usually lost. 

While chemical warfare agents have been used for decades in military conflict, it is only in the last two decades that increasing attention has been placed on the acute and chronic health effects associated with exposure to these agents. The Gulf War of 1991 and the subsequent reports of ill-defined illnesses in the veterans of that conflict, followed by the 1995 sarin terrorist event in the Japanese subway system, placed increased attention on the capacity of deliberate or accidental exposure to chemical warfare agents resulting in significant human death and subsequent disability. 

Perocular Route. The administration of drugs or accidental exposure of chemicals to the eyes is not commonly a concern in systemic toxicity due to the small surface area exposed and the efficiency of the protective mechanisms (i.e., blink reflex and tears). As long as the epithelium of the eyes remains intact, it is impermeable to many molecules, but, if the toxicant has a suitable polar-nonpolar balance, penetration may occur (Kondrizer et al., 1959 Swan and White, 1972). 

Accidental releases of agent or other hazardous materials are expected to be no more likely for a SILVER II plant than for plants using other technologies for destruction of agent. The most significant source of accidental exposure to the public remains the rockets in storage and transport to the chemical demilitarization facility. 

Of three chemical workers who were observed after accidental exposures to perchloromethyl mercaptan, two survived episodes of pulmonary edema, and the third died after 36 hours. The fatality resulted from a spill of the liquid on the clothing and floor with exposure to the vapor. At autopsy, there was necrotizing tracheitis, massive hemorrhagic pulmonary edema, marked toxic nephrosis, and vacuolization of centrilobular hepatic cells. 

Paraquat and the related chemical diquat are nonselective herbicides that are also toxic to mammals. Occupational or accidental exposure to paraquat can be from oral ingestion, dermal exposure, or inhalation, all of which can cause serious illness or death. While seldom used in the United States, paraquat is still widely used in developing countries. At one time it was used to kill marijuana plants, but a number of fatalities were observed when marijuana contaminated with paraquat was inhaled. 

This chapter discusses CSDP monitoring of employee health status as it relates to the workplace. A responsible industrial operation involving hazardous substances must have an effective occupational and environmental health program to monitor workers for health effects that might result from unknown exposures to chemical or physical agents during normal operations or from accidental exposures during upset conditions. 

Sonneborn, T, M, ed, 1965, The Control of Human Heredity and Evolution. New York Macmillan, Sparrow, A, H, and L, A, Schairer, 1971, Mutational response in Tradescantia after accidental exposure to a chemical mutagen, EMS Newsletter 1 16-19,... 

Ocular Effects. Chemical burns to the eyes were reported in humans after accidental exposure to uranium hexafluoride (Kathren and Moore 1986). Conjunctivitis and eye irritation have also been reported in animals after exposure to uranium hexafluoride (Spiegl 1949) and to uranium tetrachloride (Dygert 1949a). Ocular effects were due to direct contact of the eye with vapor or aerosols. 

Most studies on the action of phosgene oxime have utilized animal studies. Human information has been obtained from accidental exposure to the chemical. Health effects following phosgene oxime exposure are dependent on the route of exposure. 

Assurances that new and existing chemical processes are conducted safely have never been more needed. Public awareness of the effects of chemical exposure has increased since the early 1970s. Although the initial focus of the Occupational Safety and Health Act of 1970 was on safety, clearly the emphasis now is on health. People at all levels of society are concerned about exposure to chemicals and the possible short- and longterm effects of chemicals on human health. The effects of chemicals on the environment from past or present waste sites, accidental releases or spills, and fires and explosions are reported daily in the news media. Control of all chemical processes to avoid accidental discharges and/or upsets that lead to fires, explosions, and environmental release is essential in the laboratory, the pilot plant, and the manufacturing plant. Chemical process hazard reviews are necessary at each step in the development of a process to ensure that the process can be controlled and conducted so as to minimize the risks to personnel, property, and the environment. 

Chemical warfare agents were not used in World War n, although both sides had the capability. Reports have surfaced that chemical agents were used in experiments conducted on concentration camp prisoners, by both the Third Reich and Japan. An accidental exposure to mustard did occur during World War II when a tanker was sunk and mustard leaked and contaminated the waters of an Italian port. Survivors rescued from the sinking ship developed classic skin lesions associated with sulfur mustard. 

There have been data obtained from direct human exposures due to accidental exposures to hi levels of a number of hazardous chemicals. These, of course, are not controlled experiments and the dose levels must be inferred from the circumstances of the incident, but as direct evidence of the results of high exposures, they are extremely useful. 

While accidental exposure to the skin for most chemicals is almost always remediated by flushing with water, since these chemicals react with water the best first remedy is to remove the solid, usually scraping it away with something (e.g., a credit card). Then, flushing with copious amounts of water is effective since only traces of the compound will remain and the exothermicity of the reaction will be tempered by the heat capacity of the water. 

Fishermen periodically recover chemical weapons and are burned through accidental exposure to sulphur mustard. This is because when sulphur mustard comes in contact with cold water a tarry substance forms around the exterior while the interior remains viscous over a period of many decades. The exterior consists mainly of precipitates derived from thickening agents (Fishermen then break open the crusty exteriors as they haul their catches into their boats and may then become exposed or contaminate their vessels as a result). The chemical composition of the tarry exterior is not well understood partly because it varies from case to case. Various polymer materials, such as alloprene and poly [methyl methacrylate] (PMMA), for example, were sometimes combined with sulphur mustard to lower its freezing temperature. Solvents such as chlorobenzene, have also been combined with sulphur mustard. Finally, sulphur mustard was often mixed with arsenic-containing agents, such as lewisite and diphenychloroarsine. 

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