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750 Introduction to Industrial Hygiene
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Reducing Exposures

To reduce exposures to hazardous chemicals, everyone who works with toxic substances should know the names, toxicity and other hazards of the substances they use.

Employers are required by law to provide this information, along with training in how to use toxic substances safely. A worker may obtain information about a chemical's composition, physical characteristics, and toxicity from the Safety Data Sheet (SDS).

Engineering Controls. Limiting exposure at the source is the preferred way to protect workers. The types of engineering controls, in order of effectiveness, are:

Substitution. Substitution is using a less hazardous substance. But before choosing a substitute, carefully consider its physical and health hazards. For example, mineral spirits (Stoddard Solvent) is less of a health hazard than perchloroethylene for dry cleaning, but is more of a fire hazard and an air pollutant.

Enclosure/Isolation. Process or equipment enclosure is the isolation of the source of exposure, often through automation. This completely eliminates the routine exposure of workers. For example, handling of radioactive materials is often done by mechanical arms or robots.

Ventilation. Local exhaust ventilation is a hood or air intake at or over the source of exposure to capture or draw contaminated air from its source before it spreads into the room and into your breathing zone. General or dilution ventilation is continual replacement and circulation of fresh air sufficient to keep concentrations of toxic substances diluted below hazardous levels.

Personal Protective Equipment. Personal protective equipment (respirators, gloves, googles, aprons) should be used only when engineering controls are not possible or are not sufficient to reduce exposure.

Respiratory Protective Equipment. Respiratory protective equipment consists of devices that cover the mouth and nose to prevent substances in the air from being inhaled. A respirator is effective only when used as part of a comprehensive program established by the employer, which includes measurement of concentrations of all hazardous substances, selection of the proper respirator, training the worker in its proper use, fitting of the respirator to the worker, maintenance, and replacement of parts when necessary.

Protective Clothing. Protective clothing includes gloves, aprons, goggles, boots, face shields, and any other materials worn as protection. It should be made of material designed to resist penetration by the particular chemical being used. The manufacturer of the protective clothing usually can provide some information regarding the substances that are effectively blocked.

Barrier Creams. Barrier creams are special lotions used to coat the skin and prevent chemicals from reaching it. They may be helpful when the type of work prevents the use of gloves. However, barrier creams are not recommended as substitutes for gloves. Cosmetic skin creams and lotions (such as moisturizing lotion) are not barrier creams.

Knowledge Check Choose the best answer for the question.

1-5. Which two of the hazard control solutions would completely eliminate routine exposure to hazards.