In the workplace, the skin is an important route of exposure to chemicals and other contaminants," says NIOSH. Occupational skin diseases, mostly allergic and irritant dermatitis, are the second most common type of occupational disease. In 1997, there were nearly 57,000 cases of occupational skin disease, a number widely believed to be only a fraction of the true incidence.
Yet, some safety and health experts say the industrial hygiene community has failed to adequately appeciate the role that exposure of the skin, often via the hands, to chemicals plays in the development of workplace diseases.
"In general, dermal exposure is not a widely recognized pathway for worker exposure. So much attention is paid to the inhalation pathway, which is really driven by regulatory practices," says Timothy J Buckley, Ph.D., an assistant professor of environmental health engineering at Johns Hopkins School of Hygiene and Public Health. "What we're becoming more and more aware of is that the dermal pathway can result in very high levels of worker exposure and can exceed that which is occurring by inhalation. Relative to inhalation, it can be viewed as a forgotten pathway."
Tom Klingner, laboratory manager for CLI Laboratories, Des Plaines, Ill., argues that industrial hygienists have focused almost exclusively on airborne exposures, developing continually lower and more expensive standards for air contamination, while largely ignoring the contribution of dermal exposure.
Klingner points to the case of an automobile painting facility that had taken extensive measures to control worker exposure to isocyanates, a major cause of occupational asthma. Workers wore "moon suits" hooked up to outside-supplied air sources. Low-pressure nozzles were used to reduce excess spray. Despite these measures, workers continued to develop asthma. Management suspected that workers were painting cars at home, where they did not have PPE or filtered air.
Instead, investigators found that after use, spray nozzles would be placed in a bucket of solvents to clean off the paint. At the end of their shift, workers would stick their bare hands in the solvents. The isocyanates had dissolved in the solvents. Because the solvents helped to destroy the protective barrier properties of the skin, says Klingner, the isocyanates were able to easily penetrate the workers' skin.
In another case, a facility was performing biological monitoring of a group of employees working with chemicals, including aromatic amines, suspected or known to cause cancer in humans. This group was monitored on a quarterly basis. As an added precaution, a broad crosssection of plant employees was monitored annually to check for unforeseen exposures. Three maintenance workers were tested. The maintenance worker who did work on the machines used with these chemicals showed little exposure, but the other two, who never worked near these chemicals, showed the highest levels of exposure among the plant population. The employer said the monitoring results must be flawed.
Upon further investigation, the employer found that the two maintenance employees were taking their co-worker's tools. Those tools were heavily contaminated with the chemicals. While he wore chemical-resistant gloves when handling the tools, the other two did not, resulting in skin exposure. The employer decontaminated the tools, painted them red and restricted their use. A month later, the two maintenance workers showed a significant drop in their exposures.
Protecting the Hands
In recent years, manufacturers of chemical protective gloves have provided a variety of guides, both written and online, to help company managers choose the glove appropriate for a specific chemical exposure.
Even with such selection aids, choosing the right glove can be daunting. Permeation and degradation information for gloves usually involves single chemicals, rather than the mixtures to which workers may actually be exposed. Work situations may place multiple, even conflicting, requirements on gloves for dexterity, tear resistance and other usage factors.
Skin care also plays a role in the protection of the hands. While the majority of occupational dermatitis cases, says Jeffrey Stull, president of International Personnel Protection Inc., Austin, Texas, result from not using gloves or misusing gloves, an added factor in both cases is the failure of workers to take care of their skin, which results in the skin providing a less effective barrier to foreign substances.
In the end, experts agree, there is no perfect glove barrier material. Safety professionals need to appreciate the significant role that skin exposure can play in occupational disease, provide the best choices of protective gloves and make sure that employees use the gloves in an approriate manner.
Hand Protection Tips
- All chemicals permeate through protection clothing, sooner or later.
- When you have permeation, you are in contact with the chemical.
- When a glove degrades, it is much too late.
- Some gloves can be very resistant and still be permeated by a chemical.
- No single glove gives absolute protection against all chemicals.
- A glove can perform well against one chemical and poorly against a closely related chemical.
- Gloves may appear alike in material and color, but manufacturing procedures greatly affect performance.
- If you double the thickness, you quadruple the breakthrough time.
- A higher temperature usually makes gloves fail sooner.
- The best way to select a glove is to have it tested against the chemical(s) you use under the conditions you use them.
- Wash your hands before eating or smoking.
- Wash your hands before visits to the rest room.
- Wash your hands before putting on and after taking off gloves.
- Remove gloves correctly. Never touch the outside of gloves.
- Wash your gloves before you take them off.
- Dispose of gloves early and often.