Worker Health Study Summaries
Research on long-term exposure
Aerospace Workers (fluorocarbon FC 113 (Freon 113))
The National Institute for Occupational Safety and Health (NIOSH) conducted a study which included workers who clean aerospace components for NASA. The workers may have been exposed to Freon 113 also known as fluorocarbon FC 113. NIOSH collected and analyzed air samples from 31 persons in the two facilities. NIOSH then measured for irregular heart beats with heart monitors. We also interviewed workers.
The results suggest that the measured levels of FC 113 exposures at these two facilities did not place workers at increased risk of heart monitor changes (cardiac dysrhythmias or small changes in cardiac activity).
The study took place in January and February of 1990, and it included 31 aerospace workers exposed to FC 113. To conduct this research, NIOSH collected exposure and heart monitor data on 21 workers and interview data on each of the 31 workers.
The levels of FC 113 exposure seen did not cause heart monitor changes (cardiac dysrhythmias or small changes in cardiac activity). However, these results may not apply to other groups of workers who are not as healthy or do more physically demanding work.
All measured 8-hour TWA exposures were below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) and the NIOSH recommended exposure limit (REL) of 1000 parts per million (ppm). One short-term exposure measurement taken during the sampling task was found to exceed the OSHA Short-Term Exposure Limit (STEL) and the NIOSH recommended short-term exposure limit (RSTEL) of 1250 ppm. This was probably due to the nearness of the breathing zone to the point of FC 113 application to the part being cleaned. However, no discernable effect of peak short-term exposures on heart monitor changes (cardiac dysrhythmias or small changes in cardiac activity) were seen.
Of the five tasks associated with the cleaning process, the sampling task is associated with the greatest exposure to FC 113. Employees performing the sampling task should maximize the distance between their breathing zone and the point of FC 113 application to the part being cleaned. This would allow FC 113 vapors to be carried away from the breathing zone.
If you have any questions or would like a copy of the final report which is known as HETA 89-344-2157, please call the NIOSH toll free number: 800-356-4674. Say you're calling about the Freon® study.
TWA (time-weighted average)
This is a way of measuring the total exposure of a worker to contaminants in work room air in a work day.
Permissible Exposure Limit (PEL)
This is a legal exposure limit established by OSHA for TWA exposures in any 8-hour work shift during a 40-hour work week.
Recommended Exposure Limit (REL)
These is an exposure limit recommended by NIOSH for TWA exposures in any 10-hour work shift during a 40-hour work week.
Short-Term Exposure Limit (STEL)
This is a legal 15-minute TWA exposure limit established by OSHA that cannot be exceeded at any time during a work day.
Recommended Short-Term Exposure Limit (RSTEL)
This is a 15-minute TWA exposure limit recommended by NIOSH that should not be exceeded at any time during a work day.
- Page last reviewed: October 1, 2015
- Page last updated: July 13, 2012
- Content source:
- National Institute for Occupational Safety and Health (NIOSH) Office of the Director