Preventing exposure to toxic chemicals is a main concern at many workplaces such as hazardous waste sites. Workers are often required to handle a variety of chemicals in solid, liquid, or gaseous form. These substances can come into contact with or enter the body through several routes of exposure:
- Inhalation, which is often the most concerning as the lungs are very vulnerable to chemicals. Substances that do not have a direct impact on the lungs may pass through and into the bloodstream, where they are transferred to the rest of the body.
- Direct contact with the eyes or the skin. Some chemicals cause direct injury and others may pass into the bloodstream. Cuts and abrasions enhance the absorption, and the eyes are vulnerable in particular due to their moist surface.
- Ingestion, the least significant route. Although direct ingestion of chemicals is uncommon, it may still occur due to personal habits such as chewing tobacco or gum, smoking, eating, and drinking on site.
- Injection, during which chemicals enter the body through puncture wounds. This often occurs by a worker tripping and falling onto sharp objects that are contaminated.
Exposure to chemicals is generally classified by two categories: acute (short-term) exposure and chronic (long-term) exposure. Examples of acute exposure include using nail polish remover or cleaning with a substance such as ammonia. Although periods of exposure may be few and far between, even short contact with certain toxic chemicals may lead to serious health effects.
The specific effects of acute exposure depend on a variety of factors, including the chemical itself, duration of exposure, route of entry, and personal factors such as age, nutrition, medication use, alcohol consumption, and smoking habits. While often temporary, some effects are permanent and may lead to disability or death. The health impact of acute exposure may include:
- Obvious symptoms such as rashes, tearing eyes, nausea, coughing, or burning.
- Damage without any warning signs.
- Respiratory disease and cancer that manifests several years after the initial exposure.
- Dulling sense of smell.
- Tissue damage and irritation.
OSHA has determined short-term exposure limits for certain chemicals. These STELs can be used as a guideline to determine the period of time employees should be exposed before their safety may become compromised. Exact limits vary by chemical. These limits can be very helpful in determining necessary PPE, response times, and procedures in the event of accidental prolonged exposure such as a leak.
Acute Exposure Guideline Levels
The EPA has also set acute exposure guideline levels (AEGLs) and offers chemical priority lists. These guidelines describe the impact of exposure to airborne chemicals and are used by emergency responders who deal with catastrophic exposures such as chemical spills. While AEGLs were designed to be used by state and federal agencies to develop emergency preparedness in the event of an accidental chemical release or intentional attack, they may be applied to toxic industrial chemicals. AEGL levels allow workplace personnel to determine the areas of highest risk, public instruction, medical response, and evacuation if need be.
Handling toxic chemicals is an essential part of the job in many workplaces. By following guidelines established by OSHA and the EPA, as well as being aware of routes of exposure, workers can limit their contact and stay safe.