(3) The effect of chemicals on the skin may be an irritant effect, a sensitizing
effect, or both. A chemical that is classified, as a skin irritant will cause irritation to any
individual's skin, if left in contact with the skin longs enough. Most of the organic
compounds can be considered skin irritants, although they vary greatly in strength.
Chemical agents which do not cause skin disease on first contact but do so after 5 to 7
days or more of continuous or repeated contact are called sensitizing chemicals. This is
a type of allergy, which develops only in a small number of people exposed, depending
on the chemical involved and the individual's sensitivity to that substance. Examples of
chemicals capable of sensitizing are the explosives, photographic developers, epoxy
mixtures, some insecticides, and some fungicides.
c. Nervous System Effects. It is difficult to summarize the toxic effects of
organic solvents, since they vary greatly in their effects on human tissue. There is one
property, however, which is common to practically all of the organic solvents. It is their
ability to produce a loss of sensation and sometimes a loss of consciousness. Sudden
large exposures to concentrated vapors of certain solvents can lead to instant
unconsciousness and even death. With lower levels of exposure, less severe
symptoms will be experienced. Headaches, dizziness, nausea, vomiting, and
convulsions may occur. Even low exposure may produce enough drowsiness to create
an accident hazard under certain conditions. The insecticides are good examples of
these toxic properties; for example, the chlorinated hydrocarbon insecticide like DDT
acts directly on the brain and can cause tremors, dizziness, and convulsions.
Organophosphorus and carbamate insecticides such as Malathion are also organic
compounds, but they exert their toxic action on that part of the nervous system that
controls breathing, digestion, muscle strength, vision, and sweating. Thus, excessive
exposure to these chemicals results in respiratory difficulty, vomiting, muscle weakness,
blurry vision, and excessive sweating, which are but a few of the many symptoms. No
attempt will be made to describe the toxic effects of each specific chemical in this group.
d. Cancer Producing Liquid Chemicals. Brief mention should be made of the
cancer producing properties of certain liquid chemicals. In lesson l, it was mentioned
that as early as l775, cancer of the scrotum in chimney sweeps was recognized as a
hazard of that occupation. Since that time, skin cancer as been found in many other
occupations in which exposure to coal tar and pitch exists. Cancer of the urinary
bladder has been reported in workers who handle certain organic dyes. Occupational
Service Health Act has published a list of cancer producing chemicals (carcinogens)
that can be found in 29 CFR Part 1910.1000.
2-l3. PREVENTION AND CONTROL
a. General. Measures for the prevention and control of illnesses arising from
exposure to liquid chemicals fall into three groups: environmental control, personal
control, and medical control. By far the most effective category is environmental
control; this type of control involves designing the work area and associated equipment
to minimize the exposure of the worker to the liquid chemical, its vapors, or its mists.
Environmental control also includes one of the most basic control measures substituting