Common-source community and industrial exposure to trichloroethylene.

Area of Science:

• Environmental Health
• Occupational Health
• Toxicology

Background:

• A significant release of trichloroethylene (TCE) occurred in July 1979 at a pipe manufacturing plant in Montgomery County, Pennsylvania.
• The spill contaminated both ground and surface water, necessitating an evaluation of community and occupational exposure.

Purpose of the Study:

• To assess the extent of community exposure to TCE through environmental surveys of water contamination.
• To evaluate occupational exposure levels and health effects among workers at the manufacturing plant.
• To determine the impact of remediation efforts on exposure levels and worker health.

Main Methods:

• Environmental sampling of well water within 1 km of the factory to measure TCE concentrations.
• Medical surveys and biological monitoring (urinary TCE metabolites) of exposed workers.
• Air sampling to determine time-weighted and short-term occupational exposure to TCE before and after ventilation improvements.

Main Results:

• TCE concentrations in well water reached up to 183,000 parts per billion (ppb), far exceeding the EPA's proposed guideline of 5 ppb.
• Occupational exposure levels for degreaser operators exceeded recommended limits, with workers reporting symptoms like drowsiness and dizziness.
• Post-remediation, occupational exposure decreased, along with symptom frequency and urinary TCE metabolite levels.

Conclusions:

• This incident highlights the potential for a single source to cause both widespread community and significant occupational exposure to chemical toxins.
• Environmental contamination by TCE can persist, suggesting multiple release events may have occurred.
• Improvements in industrial hygiene, such as enhanced ventilation, can effectively reduce occupational exposure and associated health effects.