Wash. Admin. Code § 296-62-07339 - Appendix C-Medical surveillance guidelines for acrylonitrile
(1) Route of
entry.
(a) Inhalation;
(b) Skin absorption;
(c) Ingestion.
(2) Toxicology.
(a)
Acrylonitrile vapor is an asphyxiant due to inhibitory action on
metabolic enzyme systems. Animals exposed to 75 or 100 ppm for seven hours have
shown signs of anoxia; in some animals which died at the higher level,
cyanomethemoglobin was found in the blood. Two human fatalities from accidental
poisoning have been reported; one was caused by inhalation of an unknown
concentration of the vapor, and the other was thought to be caused by skin
absorption or inhalation. Most cases of intoxication from industrial exposure
have been mild, with rapid onset of eye irritation, headache, sneezing, and
nausea. Weakness, lightheadedness, and vomiting may also occur. Exposure to
high concentrations may produce profound weakness, asphyxia, and death. The
vapor is a severe eye irritant. Prolonged skin contact with the liquid may
result in absorption with systemic effects, and in the formation of large
blisters after a latent period of several hours. Although there is usually
little or no pain or inflammation, the affected skin resembles a second-degree
thermal burn. Solutions spilled on exposed skin, or on areas covered only by a
light layer of clothing, evaporate rapidly, leaving no irritation, or, at the
most, mild transient redness. Repeated spills on exposed skin may result in
dermatitis due to solvent effects.
(b)
Results after one year of a planned two-year animal study on the
effects of exposure to acrylonitrile have indicated that rats ingesting as
little as 35 ppm in their drinking water develop tumors of the central nervous
system. The interim results of this study have been supported by a similar
study being conducted by the same laboratory, involving exposure of rats by
inhalation of acrylonitrile vapor, which has shown similar types of tumors in
animals exposed to 80 ppm.
(c) In
addition, the preliminary results of an epidemio-logical study being performed
by duPont on a cohort of workers in their Camden, S.C. acrylic fiber plant
indicate a statistically significant increase in the incidence of colon and
lung cancers among employees exposed to acrylonitrile.
(3) Signs and symptoms of acute
overexposure. Asphyxia and death can occur from exposure to high concentrations
of acrylonitrile. Symptoms of overexposure include eye irritation, headache,
sneezing, nausea and vomiting, weakness, and light-headedness. Prolonged skin
contact can cause blisters on the skin with appearance of a second-degree burn,
but with little or no pain. Repeated skin contact may produce scaling
dermatitis.
(4) Treatment of acute
overexposure. Remove employee from exposure. Immediately flush eyes with water
and wash skin with soap or mild detergent and water. If AN has been swallowed,
and person is conscious, induce vomiting. Give artificial respiration if
indicated. More severe cases, such as those associated with loss of
consciousness, may be treated by the intravenous administration of sodium
nitrite, followed by sodium thiosulfate, although this is not as effective for
acrylonitrile poisoning as for inorganic cyanide poisoning.
(5) Surveillance and preventive
considerations.
(a) As noted above, exposure
to acrylonitrile has been linked to increased incidence of cancers of the colon
and lung in employees of the duPont acrylic fiber plant in Camden, S.C. In
addition, the animal testing of acrylonitrile has resulted in the development
of cancers of the central nervous system in rats exposed by either inhalation
or ingestion. The physician should be aware of the findings of these studies in
evaluating the health of employees exposed to acrylonitrile.
(b) Most reported acute effects of
occupational exposure to acrylonitrile are due to its ability to cause tissue
anoxia and asphyxia. The effects are similar to those caused by hydrogen
cyanide. Liquid acrylonitrile can be absorbed through the skin upon prolonged
contact. The liquid readily penetrates leather, and will produce burns of the
feet if footwear contaminated with acrylonitrile is not removed.
(c) It is important for the physician to
become familiar with the operating conditions in which exposure to
acrylonitrile may occur. Those employees with skin diseases may not tolerate
the wearing of whatever protective clothing may be necessary to protect them
from exposure. In addition, those with chronic respiratory disease may not
tolerate the wearing of negative-pressure respirators.
(d) Surveillance and screening. Medical
histories and laboratory examinations are required for each employee subject to
exposure to acrylonitrile above the action level. The employer must screen
employees for history of certain medical conditions which might place the
employee at increased risk from exposure.
(i)
Central nervous system dysfunction. Acute effects of exposure to
acrylonitrile generally involve the central nervous system. Symptoms of
acrylonitrile exposure include headache, nausea, dizziness, and general
weakness. The animal studies cited above suggest possible carcinogenic effects
of acrylonitrile on the central nervous system, since rats exposed by either
inhalation or ingestion have developed similar CNS tumors.
(ii) Respiratory disease. The duPont data
indicate an increased risk of lung cancer among employees exposed to
acrylonitrile.
(iii)
Gastrointestinal disease. The duPont data indicate an increased risk of cancer
of the colon among employees exposed to acrylonitrile. In addition, the animal
studies show possible tumor production in the stomachs of the rats in the
ingestion study.
(iv) Skin
disease. Acrylonitrile can cause skin burns when prolonged skin contact with
the liquid occurs. In addition, repeated skin contact with the liquid can cause
dermatitis.
(e)
General. The purpose of the medical procedures outlined in the standard is to
establish a baseline for future health monitoring. Persons unusually
susceptible to the effects of anoxia or those with anemia would be expected to
be at increased risk. In addition to emphasis on the CNS, respiratory and
gastro-intestinal systems, the cardiovascular system, liver, and kidney
function should also be stressed.
Notes
Statutory Authority: Chapter 49.17 RCW. 88-11-021 (Order 88-04), § 296-62-07339, filed 5/11/88.
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