Perchloroethylene (PCE), also known as perc or tetrachloroethylene, is a synthetic chemical widely used in dry cleaning and metal degreasing. PCE easily evaporates and has been found to contaminate indoor and outdoor air, groundwater, soil, and consumer products. Long-term occupational exposure to PCE is associated with increased risks of cancers like bladder cancer, lymphoma, and multiple myeloma. PCE exposure has also been linked to neurological effects even at low concentrations. Several government agencies have regulations and guidelines regarding safe exposure limits for PCE in occupational and environmental settings. Remediation of PCE contamination involves identifying responsible parties and using technologies to treat contaminated air, water, and soil.

1. Perchloroethylene
(PCE)
Presented by: Elizabeth Bemis, Holly Kingsbury, Emily Steen,
Daniel Vigil, Petra Wolford

2. What is Perc?
Perchloroethylene
Tetrachloroethylene
PCE
“Perc”
Cl2C=CCl2

3. PCE: PERC, Perchloroethylene
“A volatile organic
compound (VOC)”
In 1985, worldwide production was
about 1 million metric tons
(Rossberg 2006)
Widely used for dry
cleaning and as a metal
degreaser, in typewriter
correction fluid, and shoe
polish.
Small amounts are also
retained by recently dry
cleaned clothing

4. Where Else Can it be
Found?
•It is used as a
“building block” for
creating other
chemicals.
•Some consumer
products may
contain perc as well.

5. But, What is It?
•A synthetic chemical that at
room temperature is a
nonflammable liquid.
•An organic solvent that easily
dissolves organic material like oil
and grease.
•It easily evaporates (volatile)
and has a sharp and sweet
odor, detectable in the air at a
level of 1 ppm.

6. Occupational Exposure
Perchloroethylene
Tetrachloroethylene
PCE
“Perc”
Cl2C=CCl2

7. How does a worker get
exposed?
• Most likely exposure from the air we breathe
• Levels are usually several thousand times lower than what is found in dry
cleaning facilities, industrial operations, and waste sites.
• Exposure can also occur from contaminated groundwater, soil, food, and certain
consumer products
• Water repellants, spot removers, adhesives, and wood cleaners.
• Perc may stay in the air for several months and eventually settle into the soil and
water because of precipitation
• For an average individual not living near businesses or waste sites that use or
contain PCE, exposure is well below the maximum exposure limits provided by the
EPA for workers.
• Individuals that work with PCE are at a greater risk for adverse health effects.
• According to NIOSH more than 650,000 U.S. workers may be exposed.

8. Occupational Exposure:
Dry Cleaning
• We already know PCE can contaminate the air through evaporation from liquid solvent,
contaminated water, or contaminated soil
• Dry cleaners are a significant site of occupational exposure via inhalation:
• Risks from excessive inhalation as well
as spilling PCE solvent on exposed skin
• Loading dirty clothes into the machine
(displacement of pre-contaminated air)
• Removing clothes before the drying
cycle is finished
• Transferring solvent-laden clothes
into the dryer
• Cleaning and maintaining machines
• Possible: Pressing freshly dry-cleaned
clothes

9. Safe Exposure Limits
Organization 8-hour time weighted
average
Other limits
OSHA (mandatory) PEL: 100 PPM Ceiling: 200 ppm for 5 min
in a 3 hour period
ACGIH (voluntary) TLV: 25 ppm STEL: 100 ppm
NIOSH Minimize workplace
exposure concentrations
85% of the more than 35,000 dry
cleaners in the United States use
PCE as a solvent in the dry cleaning
process.

10. Health Risks with Exposure
Perchloroethylene
Tetrachloroethylene
PCE
“Perc”
Cl2C=CCl2

11. What Are The Risks Of Exposure?

12. Harm From Exposure: Cancer
EPA 2013: “likely to be carcinogenic to humans”
Human Epi Studies
•Occupational exposure
•Increased risk of
Bladder cancer,
Lymphoma and Multiple
Myeloma
•Dose Response
Animal Studies
•Clear carcinogen
•Leukemia and liver
cancer were caused in
multiple studies
•Kidney, brain and
testicular cancer also
seen

13. Harm From Exposure: Neuro
EPA 2013: “Neurotoxicity was supported by considerable
evidence...and at lower concentrations”
Human Epi Studies
•Occupational or
Residential exposure
•Deficits in Visual Acuity
and Memory, Cognitive
Function, and Reaction
Times
•Levels as low as 0.7ppm
Animal Studies
•Same effects seen
•Changes in the
cerebellum, frontal
cortex & hippocampus
•Brain DNA, RNA,
protein and lipid
composition altered

14. Harm From Exposure:
What about me?
• Occupational exposure
is in the range of
60ppm
• Apartments sharing a
building with dry-
cleaners ~0.7ppm
• Dry-cleaned clothes in
a vehicle ranged from
<0.1 to >3ppm
• Outdoor air near an
industrial
contamination site
<0.001ppm
• PCE is highly
concentrated in
breast milk

15. How Can PCE Be
Cleaned/Reduced?
Perchloroethylene
Tetrachloroethylene
PCE
“Perc”
Cl2C=CCl2

16. PCE and Surface Discharge

17. Underground Plumes in
Colorado
• There are at least 86
underground plumes
(from PERC) in
Colorado!
• 350 Dry Cleaners are
currently using PERC
in Colorado alone. It is
still legal to use.

18. Remediation Technologies
The first step is to find Potentially
Responsible Parties (PRPs) and
discover each PRP’s allocated portion
(responsibility)
Plumes are massive, cover miles and
involve numerous contributing
sources.
Remediation is extremely expensive
and involves years of litigation.

19. What Policies Are In Place?
Perchloroethylene
Tetrachloroethylene
PCE
“Perc”
Cl2C=CCl2

23. Conclusion
National and State regulations have
helped in reducing harmful levels of
PERC in the air.
Because of epidemiological studies
we now know the harmful effects of
PERC and can better protect workers
and the public through remediation
activities and air and water quality
regulations.
Requirement of “no new PERC dry
cleaning facilities” offers a promising
end to the PERC dry cleaning story.

24. References
• Agency for Toxic Substances and Disease Registry. (1997). "Toxicological Profile For Tetrachloroethylene". Atlanta, GA, p. 174. Retrieved
2012-09-16. citing C&EN, 1994, Facts and Figures for the Chemical Industry, Chemical and Engineering News, July 4, 1994.
• Agency for Toxic Substances and Disease Registry (1997). Public health statement: tetrachloroethylene. CAS#: 127-17-4. Available at:
http://www.atsdr.cdc.gov/ToxProfiles/tp18-c1-b.pdf. Accessed April 3, 2014.
• Environmental Protection Agency (2011). Removal of “Perc’ Pollution Begins at Former Cleaners
http://www.epa.gov/region5/cleanup/sandies/pdf/sandies_fs_09212011.pdf
• Environmental Protection Agency. (2012). Toxicological Review of Tetrachloroethylene (CAS No. 127-18-4).
• Ferroni C, et.al. (1992). Neurobehavioral and neuroendocrine effects of occupational exposure to perchloroethylene, Neurotoxicology,
13:243-247.
• Gold, Laura S. et.al. (2011). The Relationship between Multiple Myeloma and Occupational Exposure to Six Chlorinated Solvents;
Occupational and Environmental Medicine, 68(6): 391-399.
• Henshaw, S. (2013). Enviroforensics.com When Contaminated Groundwater Plumes Run Together, How is the Cost of Cleanup Divided?
Available at: http://www.enviroforensics.com/commingled-plumes-who-is-responsible-for-the-cleanup/
• National Center for Environmental Assessment, US Environmental Protection Agency. (2014). Human Health Effects of
Tetrachloroethylene: Key Findings and Scientific Issues. Available at: http://ehp.niehs.nih.gov/1307359/#tab2.
• NIOSH. (1994b). NIOSH manual of analytical methods. Third edition. Second supplement. Cincinnati, OH: NIOSH, U.S. Department of
Health and Human Services, National Institute for Occupational Safety and Health, NIOSH method no. 1003.
• Occupational Safety and Health Administration (2005). Reducing worker exposure to perchloroethylene (perc) in dry cleaning. Available at:
https://www.osha.gov/dsg/guidance/perc.html. Accessed April 3, 2014.
• Rossberg, M., et al. (2006). “Chlorinated Hydrocarbons” in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim.
doi:10.1002/14356007.a06_233.pub2
• Seidler, A., et. al. (2007). Solvent exposure and malignant lymphoma: a population-based case-control study in Germany; Journal of
Occupational Medicine and Toxicology, 2:2.
• Stevens, Y., and Eisenmann, C. (1997). Toxicological Profile for Tetrachloroethylene. Retrieved from
http://www.atsdr.cdc.gov/toxprofiles/tp18.pdf.
• Tetracholorethylene (2006) Concise International Chemical Assessment Document 68. Available at:
http://www.who.int/ipcs/publications/cicad/cicad68.pdf.