Acute Exposure

What Does Acute Exposure Mean?

Acute exposure refers to a single exposure, lasting no longer than a day, to a substance or condition that could cause harm.

The term is used to differentiate short-term exposures from ongoing or chronic exposures, which occur over a long period and can result in cumulative negative health effects.

While acute exposure tends to create immediate health effects, these effects are more likely to be reversible than those associated with chronic exposure to dangerous substances.

Safeopedia Explains Acute Exposure

The potential health effects of acute exposure include irritation (rashes and dry skin), corrosivity (burns or dissolving skin tissue), sensitization (allergic reactions, including anaphylactic shock), and death.

These effects are defined by the American National Standards Institute (ANSI) for precautionary labeling of hazardous industrial chemicals (Z 129.1-1988) but this standard does not cover the wide range of effects that may occur due to acute occupational exposure.

Some examples of acute exposure include:

• Itchiness from exposure to fiberglass
• Temporary hearing loss due to an extremely loud noise
• Loss of consciousness as a result of inhaling carbon monoxide (CO)
• Burns caused by corrosive chemicals
• Respiratory distress due to inhalation of polluted air, such as exhaust

Acute Exposure Guideline Levels

The Environmental Protection Agency (EPA) provides acute exposure levels for many chemicals. These acute exposure guideline levels (AEGLs) are used by emergency planners and responders as guidance in dealing with rare, usually accidental releases of chemicals into the air. AEGLs are expressed as specific concentrations of airborne chemicals (in parts per million or miligrams per cubic meter) that may adversely affect the health of individuals.

A chemical may have up to three AEGL values for a given duration of exposure. Each of these corresponds to a specific tier of health issues that the general population may experience as a result of the exposure:

• AEGL-1 – Could experience notable discomfort, irritation, or certain asymptomatic non-sensory effects. The effects, however, are not disabling, are transient, and are reversible when exposure is stopped.
• AEGL-2 – Could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape.
• AEGL-3 – Could experience life-threatening health effects or death.

How Are AEGLs Used

Each defined chemical has AEGL values for five exposure durations and the most appropriate duration for a particular release to be used. AEGLs should be used to protect the public where there has been a short-term release incident.

There are, however, two exceptions:

• AEGLs should not be used as guidance for workers who are routinely exposed to chemicals for longer durations. In these cases, workplace exposure limits should be used.
• AEGLs should not be used for individuals of the public who are exposed to background chemical releases for longer durations. Instead, values such as the National Ambient Air Quality Standards (NAAQS) should be used.