July 2007
Airborne Asbestos Concentrations Associated with Heavy Equipment Brake Removal.
Our Challenge
- We designed and conducted a simulation study to assess the possible exposures to airborne asbestos during removal and disassembly of asbestos-containing brakes from heavy construction equipment manufactured during the1960-1980 timeframe.
Our Approach
- Focused on heavy agricultural or construction vehicles manufactured between 1960 and 1980.
- Characterized the airborne concentrations of asbestos to workers and bystanders from brake wear debris during brake removal.
- Fiber distribution by size and morphology was evaluated using International Organization for Standardization method.
- 8-hour time weighted average airborne concentration were calculated and compared to historical and current occupational exposure limits.
Our Findings
- The results indicated that 8 hour TWA airborne concentrations for worker and bystander samples were at least 10 fold less than the current.
- Approximately 2% of the respirable fibers were greater than 20 µm in length.
- Approximately 95% of chrysotile in the brakes degraded into forsterite.