Occupational toxicology

As of 1983, around 60,000 chemical compounds were considered to be of occupational consequence. Certain sectors have an increased potential for exposure to chemical and biological agents, including manufacturing, construction, mining, logging, and agriculture, as well as service sector workplaces such as in automobile repair, gasoline stations, pipelines, truck and rail transportation, waste management and remediation, and botanical gardens. These sectors contain an increased risk of exposure largely due to the fact that they are working with heavy machinery that can emit potentially harmful fumes when being operated. Additionally, these sectors involve directly handling various substances that can possibly contain harmful chemical compounds. Toxicological studies are experimental laboratory studies on the response of organisms and biological pathways to a substance, and can generate data that are used for other occupational safety and health activities. To discover if a compound is toxic/carcinogenic, toxicologists expose mice to the compound being studied and examine them over a given amount of time. These toxicologists then look for any patterns in the mice that may suggest toxicity or carcinogenicity and draw a conclusion from this data. == Goals ==

Occupational toxicology generates data that is used to identify hazards and their physiological effects, and quantify dose–response relationships. A major use of this data is for establishing standards and regulation. These may take the form of occupational exposure limits, which are based on ambient concentration levels of toxicants. They also include biological exposure indices, which are based on biomonitoring of a toxicant, its metabolites, or other biomarkers. == Challenges ==

Occupational toxicology has the challenge of performing studies that mimic actual workplace conditions, for which inhalation exposure and dermal exposure are most important, Establishing a causal relationship between a worker's illness and work conditions is often difficult because work-related illnesses are often indistinguishable from those with other causes, and there may be a long interval between the exposure and the onset of disease. == Methods ==

Occupational toxicology uses methods common to other forms of toxicology. Animal testing is used to identify adverse effects and establish acceptable exposure levels, as well as studying the mechanism of action and dose–response relationship. There are a number of in vitro alternatives to animal testing in a number of specific cases such as predicting skin sensitizers and potential for eye injuries, as well as quantitative structure–activity relationship models. Sometimes, controlled human challenge studies are performed in cases where the risk for volunteers is negligible; these are used to verify whether results from animal studies translate to humans. Experimentation may focus on the operation and regulation of biotransformation processes that may detoxify or activate toxins. These processes are subject to difference between individuals, which is studied through the field of toxicogenomics. == History ==

While the health hazards of substances used in the workplace have been recognized since antiquity, the first experimental studies of hazardous substances came in the late 19th and early 20th centuries, including the work of John Scott Haldane on mine gases, Karl Bernhard Lehmann on organic substances, and Ernest Kennaway on occupational skin cancer. Biomarkers began to be used in occupational toxicology and epidemiology in the 1970s, and the 1990s showed increasing focus on molecular mechanisms such as identifying specific enzymes that interact with toxicants and studying their variation across individuals. == See also ==