Office of Pollution Prevention and Toxics

Strategies to Reduce Worker 

Exposure to TCE during Degreasing

Expert Public Workshop on Alternatives and Risk Reduction 

Approaches to TCE Use as a Degreaser

July 30, 2014

Presenter: Edward Viveiros (Eastern Research Group, Inc.)
Office of Pollution Prevention and Toxics 1

• Background

• Overview: Degreasing at Commercial Facilities

• Technologies That Eliminate or Reduce Risks from TCE

• Engineering Controls

• Workplace Practices

• Personal Protective Equipment

• Questions
Office of Pollution Prevention and Toxics 2

• EPA risk assessment of TCE identified health risks from:

– Commercial and consumer use of TCE as a solvent degreaser

– Commercial use of TCE as a spotting agent at dry-cleaning facilities

– Consumer use of TCE as an arts and crafts spray coating

• TCE use concerns:

– Frequent application of TCE at high concentrations

– High potential for human exposure through:

• Inhalation (predominant route due to TCE’s volatility)

• Skin absorption

• To manage TCE risks, EPA developed an outreach document to 

inform commercial stakeholders of risk reduction options
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• This guide provides a set of 

practicable and relevant 

options for reducing TCE 

risks

• Risk reduction options are 

based on:

– Literature review

– Interviews with experts
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• Identifies:

– Typical TCE degreaser use methods

– Typical commercial settings (for 

targeted communication of risk 

reduction options)

• Addresses four key risk reduction 

areas:

– Technologies to eliminate or reduce 

TCE risks

– Engineering controls

– Workplace practices

– Personal protective equipment (PPE)
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Elimination

Substitution

Engineering Controls

Workplace Practices

Personal Protective Equipment

• Basis for the key risk 

reduction areas: the 

Hierarchy of Hazard 

Control
Office of Pollution Prevention and Toxics 6

Elimination

Substitution

Engineering Controls

Workplace Practices

Personal Protective Equipment

• Basis for the key risk 

reduction areas: the 

Hierarchy of Hazard 

Control

Outside of Scope
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Typical Degreasing Methods
Office of Pollution Prevention and Toxics 8

Typical Degreasing Methods

Spot Cleaning
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Spot cleaning

• Components are cleaned by:

– Spraying degreaser directly onto components

– Wiping with a rag that has been dabbed or soaked in degreaser

• This method typically:

– Applies degreasers in excess amounts

– Readily produces TCE vapors during subsequent air drying
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Typical Degreasing Methods

Spot Cleaning Cold Cleaning
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Cold cleaning

• Components are cleaned 

in a non-boiling (“cold”) 

solvent

• Cleaning occurs by:

– Spraying

– Brushing

– Flushing

– Immersion
Office of Pollution Prevention and Toxics 12

Typical Degreasing Methods

Spot Cleaning Cold Cleaning Vapor 

Degreasing
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Vapor degreasing

• Degreaser is boiled to 

produce hot vapors 

• Components are 

suspended in the vapor 

for a set period of time

• Vapors gradually 

condense on the 

component’s surface, 

cleaning it in the process
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Typical Degreaser Users
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Typical Degreaser Users

Repair Shops
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Typical Degreaser Users

Repair Shops Fabrication Shops
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Office of Pollution Prevention and Toxics 19

Typical Degreaser Users

Repair Shops

Metal Plating Shops

Fabrication Shops
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Office of Pollution Prevention and Toxics 21

Typical Degreaser Users

Repair Shops

Metal Plating Shops

Fabrication Shops

Electronics Assembly 

Shops
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Office of Pollution Prevention and Toxics 23
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• Available risk reduction options are not exclusive to these shops

• Any facility can implement risk reduction options if they use:

– Spot cleaning

– Cold cleaning

– Vapor degreasing
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Elimination

Substitution

Engineering Controls

Workplace Practices

Personal Protective Equipment
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• For a given shop, the most suitable option can depend on:

– The cleaning process already in use

– The nature of the components being cleaned (material, shape, texture)

– The types of contaminants being removed (oils, greases, dirt, salts)

– The required level of cleaning

• Because degreasing processes, settings, and deciding factors are 

varied, it is difficult for EPA to provide detailed recommendations

• Therefore, the guide highlights practicable and relevant technologies 

that shops can consider implementing

• Ultimately, shops must work with vendors to identify the most 

suitable option
Office of Pollution Prevention and Toxics 27

Bake-off oven

• Applies to automobile, motorcycle, or bicycle repair shops

• Decomposes dirt and grease, leaving behind dry residues that 

can be brushed off

• Produces a smaller volume of waste compared to liquid 

cleaning alternatives (EPA, 1991)

• Bake-off ovens can only be used on components that can 

withstand high heat
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Water-based cleaning

• Applies to any type of shop

• Eliminates use of TCE and solvents

• Degree of elimination ranges from complete (aqueous cleaning) to partial 

(semi-aqueous)

• Utilizes the following cleaning methods:

– Manual cleaning

– Hot soap washing (hot tank washing)

– Spray cleaning

– Ultrasonic cleaning
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Low-solids fluxes

• Applies to electronics repair and assembly shops

• Are used similarly to conventional fluxes

• Dry rapidly and leave behind little or no residue, eliminating 

the need for cleaning with TCE
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Inert atmosphere soldering

• Applies to electronics repair and assembly shops

• Soldering occurs in an oxygen-free environment (typically in 

nitrogen gas)

• The inert environment prevents formation of oxide 

contaminants, eliminating the need for cleaning with TCE

• Suitability of this technology is case specific – flux still may be 

required even if soldering in an inert environment
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Closed-loop vapor degreasing

• Applies to any shop type

• Cleans components in an air-tight chamber, which:

– Significantly reduces emissions

– Improves overall cleaning and product quality

• Reduces exposures by exhausting vapors before workers can open 

the chamber door

• Reduces vapor emissions by as much as 98% compared to 

conventional vapor degreasers (NEWMOA, 2001)
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Elimination

Substitution

Engineering Controls

Workplace Practices

Personal Protective Equipment
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• Mechanical Ventilation

– Removes “dirty” air from within the shop

– Supplies “fresh” air to the shop

• Local exhaust ventilation

– Provides exhaust ventilation close to the cleaning station

– Captures and removes TCE vapors surrounding the source, before they 

enter other areas of the shop

• Because of the direct nature of spot cleaning, engineering 

control options for preventing direct contact with TCE are 

limited to ventilation
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• Limit escape of TCE vapors from cleaning tank by:

– Installing vapor-tight covers (rolling covers are preferable since hinged 

covers can expel TCE vapors when they swing closed)

– Covering solvent bath with a 2- to 4-in water layer (EPA, 1981)

– Installing lateral exhaust systems (large cleaning tanks only; exhausts 

should pass through carbon adsorption unit to reduce shop emissions)

• If using spray equipment, consider:

– Using a solid-fluid stream sprayer

– Avoiding atomizing or shower sprayers (they generate more TCE vapors)
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• Limit escape of TCE vapors from degreaser by:

– Installing vapor-tight covers (rolling covers are preferable since hinged 

covers can expel TCE vapors when they swing closed)

– Installing a second set of cooling coils (“freeboard chillers”)

– Installing lateral exhaust systems (large cleaning tanks only; exhausts 

should pass through carbon adsorption unit to reduce shop emissions)

– Installing a pressure gauge to identify leaks (air-tight systems only)
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• Limit escape of TCE vapors from degreaser by:

– Installing vapor-tight covers (rolling covers are preferable since hinged 

covers can expel TCE vapors when they swing closed)

– Installing a second set of cooling coils (“freeboard chillers”)

– Installing lateral exhaust systems (large cleaning tanks only; exhausts 

should pass through carbon adsorption unit to reduce shop emissions)

– Installing a pressure gauge to identify leaks (air-tight systems only)

• Where feasible, consider using automated controls:

– Condenser coolant thermostat switch

– Solvent level control switch

– Vapor level control switch
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Elimination

Substitution

Engineering Controls

Workplace Practices

Personal Protective Equipment
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• Isolate cleaning activities—physically separate the cleaning 

station from the rest of the shop

• Establish guidelines on when it is absolutely necessary to clean 

components with TCE; prohibit its use otherwise

• Encourage or require employees to brush or scrape off cakedon solids prior to cleaning components
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• Keep tank/degreaser covers closed whenever possible

• Rack components in a manner that minimizes drag-out losses

• Drain cleaned components for at least 15 seconds or until 

dripping stops

• Avoid subjecting degreasing station to drafts (they can carry TCE 

vapors into surroundings)

• Maintain an appropriate freeboard ratio (75% for cold cleaners, 

100% for vapor cleaners) (KSUPPI, 2010)
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Elimination

Substitution

Engineering Controls

Workplace Practices

Personal Protective Equipment
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• PPE that can effectively protect skin against TCE

– Gloves

– Coveralls

• Specific materials and brands are listed in the guide
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• Wear chemical splash 

goggles to protect eyes 

against any splashing

• Wear face shield over 

goggles to provide extra 

protection
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• Provide eye wash stations 

near degreasing areas

• Ensure unobstructed 

access

• When exposed, rinse eyes 

for at least 15 minutes
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• Most effective respirators for TCE 

include:

– Full-facepiece respirators with positive 

pressure supplied air

– Self-contained breathing apparatus

• These respirators have an assigned 

protection factor (APF) of 10,000 

(NIOSH, 2011)

• Dust masks (N95 respirators) do 

not protect against TCE
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Questions?
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(EPA, 1981) Solvent Degreasing. AP-42 – Compilation of Air Pollutant Emission 

Factors. Vol. 1. Fifth Ed. U.S. Environmental Protection Agency. 1981.

(EPA, 1991) Guides to Pollution Prevention—The Automotive Repair Industry. U.S. 

Environmental Protection Agency. 1991.

(KSUPPI, 2010) The Smell of Success: Decreasing Air Pollution in the Kansas City Area.

Kansas State University Pollution Prevention Institute. 2010.

(NEWMOA, 2001) Pollution Prevention Technology Profile – Closed Loop Vapor Degreasing.

Northeast Waste Management Officials’ Association. 2001.

(NIOSH, 2011) Trichloroethylene. NIOSH Pocket Guide to Chemical Hazards. National 

Institute for Occupational Safety and Health. 2011.

(NJDH, 2008) Right to Know Hazardous Substance Fact Sheet: Trichloroethylene. New 

Jersey Department of Health. 2008.