Toxicology and Industrial Hygiene

Toxicology is the branch of science concerned with the natural effects of chemicals on living organisms. Toxicologists examine these effects and measure and analyze potential toxins. They can create limits of exposure for those materials. One of the fundamental concepts of toxicology is the dose-response curve. Dose-response data are typically graphed with the dose or dose function (eg, log10 dose) on the x-axis and the measured effect (response) on the y-axis. In order to discover the effects of a chemical, toxicologists determine the amount of chemical needed to get a response. Increasing the amount of the dose will increase the amount of response. The toxicologist may use alternative test methods such as in vitro testing or the traditional, or less desired, lab animal experimentation. The experiment design must best reflect possible exposure effects in humans. From these experiments, a LD50 (lethal dose to 50% of the animal population) or LC50 (lethal concentration to 50% of the animal population) is determined. When applying these results to humans, these and other factors are used to develop a proposed exposure limit. It may include a protection factor of 10X, 100X, or greater, based upon the relative toxicity of the chemical.

Industrial Hygiene is the anticipation, recognition, evaluation, and control of health hazards in the workplace. In order to apply these concepts, it is important that industrial hygienists understand the principals of toxicology that are most frequently needed to fully understand toxicological events. Industrial Hygienists use the findings of the toxicologist to ensure that workers are exposed to hazardous chemicals at only a healthful level. They develop strategies and controls to reduce exposure based on the information that toxicologists provide.
One of the basic tools of industrial hygiene is the occupational exposure limits or OELs. OELs are established by governmental organizations such as OSHA and NIOSH, scientific organizations such as the American Conference of Governmental Industrial Hygienists (ACGIH) and the American Industrial Hygiene Association (AIHA), and other private organizations. OEL-creating organizations may take the results of a number of experiments to develop their standards. Panels of industrial hygienists and scientists create the final OEL. Governmental rule-making organizations may also include labor, industry, and governmental representatives in making their OELs. In the manufacturing of pharmaceuticals new compounds and mixtures are created. There are often no available standards for the new compound. In such cases where toxicological information is not available, company standards may be developed using control banding. Control banding takes the experimental limits of similar or a band of chemicals to infer a new exposure limit. Similarly, industrial hygienists can use control banding to set OELs where there are none available.
Where hazardous chemicals are identified, the industrial hygienist will conduct air sampling, wipe sampling, and/or biological monitoring and compare these results to relevant OELs. They may then use elimination, substitution, engineering or administrative controls, or personal protective equipment to limit employee exposures.
It is important that industrial hygienists use the work of toxicologists protect workers. Just as treatment methods may be improved in medicine, the most current toxicological information and the most stringent OELs, whether private or governmental, must be used. Along with their knowledge of the chemical process, industrial hygienists must use all this critical information to best protect employees.
For more information on this topic and to discuss your company’s safety and industrial hygiene needs call OccuSafe at (214) 662-6005 or visit us at www.occusafeinc.comOccuSafe Industrial Hygiene & Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health. OccuSafe services companies of all sizes in a range of industries.

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