Description

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Context

The US Environmental Protection Agency (EPA) announced sweeping bans on trichloroethylene (TCE) and perchloroethylene (PCE) under the 2016 Toxic Substances Control Act (TSCA).

This decision is part of a broader effort to mitigate the health and environmental risks posed by toxic chemicals aligning with President Joe Biden's Cancer Moonshot initiative to reduce cancer incidence in the United States.

Details

All manufacturing, processing and uses of TCE are prohibited.Consumer uses are entirely banned.

Many commercial uses are prohibited while limited industrial applications are permitted under strict worker protection guidelines.

For industrial applications where PCE use is still allowed enhanced worker protection measures are mandated.

Trichloroethylene

Chemical Formula: C₂HCl₃

A non-flammable, volatile organic compound widely used as a solvent. It is colorless with a slightly sweet odor.

Primary Uses:

Degreasing metal parts

Used in adhesives, paint removers and cleaning fluids

Historically used as an anesthetic and analgesic (no longer common due to toxicity concerns).

Perchloroethylene

Chemical Formula: C₂Cl₄

Also a non-flammable, volatile organic compound with a slightly sweet odor. It is commonly referred to as "tetrachloroethylene."

Primary Uses:

Dry cleaning and textile processing

Metal degreasing

Production of fluorocarbons

Properties and Characteristics

Property	TCE	PCE
Physical State	Liquid	Liquid
Color	Colorless	Colorless
Odor	Sweet, chloroform-like	Sweet, ether-like
Boiling Point	~87°C	~121°C
Solubility in Water	Slightly soluble (~1.1g/L at 25°C)	Slightly soluble (~0.15g/L at 25°C)
Volatility	Highly volatile	Highly volatile
Density	~1.46 g/cm³	~1.62 g/cm³

Health Effects

Trichloroethylene

Short-term exposure:

Dizziness, headache, nausea and confusion.

High exposure can lead to loss of consciousness and even death.

Long-term exposure:

Liver and kidney damage.

Potential carcinogenic effects (linked to liver and kidney cancers).

Neurotoxicity including effects on motor and cognitive functions.

Perchloroethylene

Short-term exposure:

Irritation of skin, eyes, nose and throat.

High concentrations can cause dizziness, nausea and central nervous system depression.

Long-term exposure:

Kidney and liver damage.

Increased risk of developing certain cancers (e.g., bladder cancer).

Possible neurotoxic effects.

Environmental Impact of TCE and PCE

Both chemicals are notorious for leaching into groundwater leading to long-lasting contamination. Example: In Woburn, Massachusetts industrial dumping of TCE polluted municipal wells causing a "cancer cluster" linked to leukemia cases.

Improper disposal of TCE and PCE has contaminated vast areas with serious consequences for both ecosystems and communities.

Both TCE and PCE are stable compounds that resist natural degradation posing long-term challenges for remediation.

Regulatory Framework

Agency	TCE	PCE
EPA (USA)	Classified as a probable human carcinogen.	Classified as a probable human carcinogen.
OSHA (USA)	Workplace limit: 100 ppm (8-hour time-weighted).	Workplace limit: 100 ppm (8-hour time-weighted).
WHO	Drinking water guideline: 20 μg/L.	Drinking water guideline: 40 μg/L.
EU Reach Regulation	Restricted use in many applications.	Restricted use in many applications.

Alternatives

For TCE:

Water-based cleaners for degreasing applications.

Use of safer solvents like alcohols or hydrocarbons.

For PCE:

Hydrocarbon-based dry cleaning solvents.

Silicone-based alternatives for textile processing.

Sources:

DOWNTOEARTH

PRACTICE QUESTION

Q.With reference to Trichloroethylene (TCE) consider the following statements:

Trichloroethylene is a widely used industrial solvent classified as a carcinogen.
TCE is primarily used in the manufacturing of pharmaceuticals and vaccines.
The US EPA’s new rules mandate the use of protective measures for workers handling TCE in industrial applications.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 3 only

(d) 1, 2 and 3

Answer: (b)

Explanation:

Statement 1 is correct. Trichloroethylene is a widely used industrial solvent primarily for metal degreasing and is classified as a carcinogen linked to kidney cancer and other health risks.

Statement 2 is incorrect. TCE is not primarily used in pharmaceutical manufacturing; its main applications are industrial such as adhesives and degreasers.

Statement 3 is correct. The US EPA’s new rules under the Toxic Substances Control Act (TSCA) require stringent protective measures for workers involved in industrial uses of TCE while banning other applications.