Chemicals

A Close TSCA Review for Supersolvent TCE

The future of trichloroethylene (TCE) in an industrial process called vapor degreasing is balanced to some extent on the outcome of an EPA proposal under which the Agency would use its authority under Section 6(a) of the Toxic Substances Control Act (TSCA) to prohibit the manufacturing (including importing), processing, and distribution in commerce of TCE for that use.

chemical facility manufacturing TCE
According to the proposal, the ban is necessary because exposure to TCE resulting from vapor degreasing presents an unreasonable risk of injury to women of childbearing age and the developing fetus. But the proposal was issued under the Obama EPA in the January 19, 2017, Federal Register, 1 day before President Donald Trump took office. The proposed prohibition is supported by environmental and public health advocacy groups. However, given the strength of industry opposition to the proposed ban as it was written, there is a good chance the proposal will not be made final.

Generally, companies that use TCE in vapor degreasing argue that the “single study” the EPA used to conclude that the chemical poses a cancer danger is unreproducible and has been faulted in the scientific literature. But the more pressing issue, says industry, is that no other solvents can match the degreasing performance of TCE despite EPA’s position in the proposal that “alternatives to TCE with similar performance characteristics are readily available.”

The stance the EPA will ultimately take on the use of TCE in vapor degreasing is complicated by the June 2016 amendments to TSCA. Specifically, for a chemical substance listed in the 2014 update to the TSCA Work Plan for Chemical Assessments for which a completed risk assessment was published before the date of enactment of the amendments, TSCA Section 26(l)(4) expressly authorizes the EPA to issue 6(a) rules that are consistent with the scope of that assessment. But the Agency is not required to issue a rule on the basis of that assessment. What the amendments do require is that within 3 years (with a possible 6-month extension) the EPA complete new risk assessments for a list of 10 high-priority chemicals that includes TCE. Industry contends that the EPA should not base a Section 6(a) prohibition on what it claims is the discredited study that formed the basis of the proposal, and any action taken should follow the upcoming risk assessment.

In any event, at the request of industry, the EPA has twice extended the public comment period on the January 19 proposal; the last extension allowed comments until May 19, 2017.

14.7 Percent for Metal Degreasing

TCE is both produced in and imported into the United States; in 2011, 255 million pounds were consumed domestically. About 83.6 percent of TCE is used as an intermediate chemical for manufacturing the refrigerant HFC-134a. This use occurs in closed systems that have low potential for human exposures. About 14.7 percent of TCE is used as a solvent for degreasing metals. About 1.7 percent has other uses, including in products such as aerosol degreasers and spot cleaners.

Degreasing is important in all metalworking and maintenance operations to remove oils, greases, waxes, tars, and moisture before final surface treatments, such as galvanizing, electroplating, painting, anodizing, and application of conversion coatings. TCE has been used in degreasing operations in five main industrial groups: furniture and fixtures, fabricated metal products, electric and electronic equipment, transport equipment, and miscellaneous manufacturing industries. According to industry, TCE is a superior degreaser, mainly because of low flammability.

TSCA Section 6(c)(2)(C) directs that the EPA must consider the availability of technically and economically feasible alternatives to a chemical substance before taking action to prohibit or restrict use of that substance. In the proposal, the EPA did identify multiple alternatives, including products with hydrocarbon/mineral spirits, products that are acetone- or terpene-based, some that contain perchloroethylene or 1-bromopropane, and water- and soy-based agents. All substitutes are expected to be less hazardous than TCE, said the Agency. But industry argues that alternatives have major drawbacks. For example, Dow Chemical points out that aqueous cleaners, which are advocated by the EPA, are more costly than TCE vapor degreasing because more energy is required for heating and drying. This multistage process also requires more floor space than a vapor degreaser, says Dow. In addition, aqueous cleaning processes require large amounts of water, which may become contaminated and require treatment, another expense. Companies have also pointed out that clients, including the U.S. military, require that products they purchase be cleaned with TCE.

Common Household Hazardous Waste

Even if alternatives to the TCE in vapor degreasing are infeasible, environmental and health organizations and at least one hazardous waste agency assert that the risks associated with the chemical are still too great to allow its continued use. The Local Hazardous Waste Management Program (LHWMP) in King County, Washington, said it had direct experience with those risks. In comments on EPA’s proposal, the LHWMP said it found widespread use of TCE in the local dry-cleaning businesses where women of childbearing age work.

“The substance is pervasive,” wrote the LHWMP. “Local customers turn in TCE at our LHWMP household hazardous waste collection sites on average once a week. At LHWMP, we spend considerable effort and public funding to research safer alternatives to using hazardous products like TCE. We educate our business community about these safer alternatives. We work to ensure safe disposal of the unwanted products that we do have in our community. TCE and other chlorinated solvents are a particular problem in Washington State because of our strict dangerous waste regulations. Under our regulations, these halogenated materials are classified as environmentally persistent, so disposal is particularly challenging for small businesses. In an ideal world, these hazardous materials would not exist at all, our community would not be impacted, and there would be no need for our prevention and collection programs. Thus, efforts to ban hazardous materials such as TCE gain our strongest support.”

Feasible Alternatives

As noted, the main criticism of EPA’s proposal centers on the Agency’s assertion that alternatives to TCE used in vapor degreasing are economically and technologically feasible. Objections to that position emerged from a Small Business Advocacy Review (SBAR) panel the Agency convened in June 2016. According to comments from the Chemical Users Coalition (CUC), Small Entity Representatives (SERs) on the panel identified technological and economic obstacles to conversion of their operations to the water-based cleaners the EPA recommended.

(The CUC comprises Intel Corporation, Procter & Gamble Company, American Honda Motor Corporation, Lockheed Martin Corporation, HP Incorporated, IBM Company, The Boeing Company, General Electric Company, and Airbus S.A.S.)

“In this context, EPA received multiple, detailed comments from specific companies indicating that alternatives to TCE were technically infeasible (e.g., lack of effectiveness for small parts in the aerospace industry and for glass-to-metal seals), impractical (e.g., facility space demands and water demand of up to 10,000 gallons per day for aqueous cleaning systems), incompatible with customer (e.g. , military) specifications, and economically infeasible (e.g. , costs beyond the capability of many small businesses),” wrote the CUC.

Furthermore, the CUC is concerned that the EPA is simply not giving proper consideration to the technological evidence that has been presented by industry. While not questioning the validity of these concerns, the Agency still requested additional comments, information, and data to assist in evaluating the availability of alternatives to TCE.

“At a minimum, it is not clear what additional ‘comments, information and data’ EPA expects companies to provide, as many of the letters and questionnaire responses already in the record show that the SER participants in the SBAR process provided multiple examples to support their concerns and specific quantitative data on their operations,” wrote the CUC. “The broader concern with the proposed rule on this topic, however, is that EPA provides no clear explanation of how it considered this evidence that a TCE ban was not technically or economically feasible in deciding whether to prohibit TCE in vapor degreasing , as required under Section 6(c)(2)(C).”

The CUC further believes that EPA’s proposed timeline—a ban on TCE in commercial vapor degreasing 18 months after publication of a final rule—is not realistic. According to the CUC, the EPA based this deadline on a comment by one SER, who said a conversion to water-based cleaning could occur in 2 years. But other SERs said 4 years would be needed, particularly to address demands by certain customers, including the aerospace industry.

“More fundamentally, there were multiple SER commenters indicating that water-based cleaners would not be technically or economically feasible alternatives at all, no matter what the transition period might be,” said the CUC.

SBA Comments

The federal Small Business Administration (SBA) also has misgivings about EPA’s conclusion that environmentally preferable alternatives can equal the performance of TCE. For example, in the proposal, the EPA endorsed drop-in solvents (an alternative that could be used in an existing vapor degreasing system with only minor modifications), non-drop-in solvents, aqueous cleaning systems, other cleaning solvents (glycol ethers, soy-based cleaners, etc.), and cold cleaning with TCE. Regarding these alternatives, the SBA commented as follows:

  • Drop-in solvents include methylene chloride, 1-bromopropoane, and perchloroethylene. These can be used in existing vapor degreasing systems with some modification. Small businesses have expressed significant concerns with EPA‘s suggested use of drop-in solvents in place of TCE because they do not consider them viable alternatives in vapor degreasing. For example, these substitutes operate at temperatures incompatible with processes used by small businesses and are less stable compared to TCE. One small business that switched to 1-bromopropane incurred significant costs to upgrade their equipment ($60,000). This small business estimates that it costs twice as much as TCE on an annual basis to use 1-bromopropane. The small business added that due to compatibility issues with aluminum castings, additional cleaning solutions are required. The small business also noted that they had to refuse defense and aerospace work that specified the use of TCE.
  • Regarding non-drop-in solvents, small businesses point out that these products boil at much lower temperatures and, as a result, are harder to keep in the machine, thereby increasing worker exposure. In addition, cleaning these chemicals requires addition of a chlorinated derivative, which is flammable. Finally, small businesses say these products are 10 times more expensive per pound, and significantly more product is used because of the lower boiling point.
  • Aqueous cleaning systems incurred more expense, increased water use (triggering water permit requirements), increased energy use, increased delay (multiple stages required to reach the same cleaning), and require additional facility space.

The SBAR panel recommended that the EPA provide exemptions under Section 6(g) for critical uses for which it can obtain adequate documentation that no technically and economically feasible safer alternative is available; compliance with the ban would significantly disrupt the national economy, national security, or critical infrastructure; or the specific condition of use, as compared to reasonably available alternatives, provides a substantial benefit to health, the environment, or public policy.

Comments on EPA’s proposal are here in docket EPA-HQ-OPPT-2016-0387.

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