 |
 Controlling
chemicals in the air
 Perchloroethlylene
(PERC) is used in most dry-cleaning shops in the United States.
It is an excellent solvent for removing dirt, but overexposure to
it can harm workers’ health. PERC is a carcinogen that can damage
the liver and kidney. Overexposure can also cause headaches, dizziness,
and memory loss. PERC exposure happens as workers load and unload
clothes from dry-cleaning machines. When high concentrations of PERC
are released from the machine, exposures can adversely affect workers
in the shop as well as others. For example, in some cases, especially
in large cities, PERC emissions have resulted in complaints and lawsuits
from adjacent neighbors and businesses.
In one shop with fewer than 10 employees, the shop owner and the
employees were worried about PERC, but they were not sure how high
their exposures were. They found out that PERC concentrations in
the air around the machines could be measured. With some outside
help, various types of air sampling equipment were used to measure
PERC concentrations in parts per million. Several workers volunteered
to wear air samplers to evaluate their exposures to PERC. The air
samplers have a small, battery-operated pump that sucks air through
a filter that is clipped onto clothes near the worker’s face.
This air sampling occurred during several work days to make sure
any unusual events in the loading and unloading processes were averaged
out. Several workers were sampled for the same reason – to
average out any individual differences in work practices.
 After
several days of air sampling, the data were compared with maximum
PERC exposure allowances for workers. Videos were made for the workers
showing that their highest PERC exposures occurred while they were
near the dry-cleaning machine. They learned that in many cases,
the machine operators were exposed to amounts of PERC that exceeded
acceptable workplace standards. To reduce their exposure, the owner
put a special exhaust filter onto the machine. Then they used the
air sampling equipment again. The filter reduced some exposures
by about 90%. The filter cost about $5,000 compared to the $60,000
cost of the dry-cleaning machine.
[Source for Case 4: Earnest GS, Ewers L, Ruder A,
Petersen., MR, Kovein, RJ [2002] An Evaluation of Retrofit Engineering
Control Interventions to Reduce Perchloroethylene Exposures in Commercial
Dry-Cleaning Shops. Applied Occupational and Environmental Hygiene
, (17)2:104 - 111.]
Acknowledgements |
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