Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
-----
Trichloroethylene/TCE in Metal Finishing History Q&A
Q. I'm a researcher and I'm currently in the process of chemical cleaning to prepare steel plates for electrodeposition. I'm using trichloroethylene as per method mentioned in a research paper at doi.org/10.1016/j.surfcoat.2014.06.043
Is there a standard temperature or protocol to follow when degreasing with trichloroethylene?
- Toronto, Ontario, Canada
March 29, 2022
A. Hi Aty. TCE is probably most frequently used in a 'vapor degreaser' rather than in an immersion or solvent wiping situation.
A vapor degreaser is an open-top tank which basically has three vertical levels:
- The bottom level is a reservoir of liquid which is heated so that it fumes. The work may or may not be initially dipped into this reservoir.
- The middle level is where most of the work is done. Objects to be degreased are cold or at least room temperature, so when they are lowered into that middle level the vapors condense on them, then run down into the reservoir, ideally carrying away the dirt and grease.
- The top level has refrigeration coils which cause the vapor to condense and fall back into the reservoir instead of escaping into the environment.
But as you might surmise from the thread we've attached your inquiry to, vapor degreasing with trichlorethylene is not nearly as common as in bygone days. These days aqueous cleaning is done instead whenever it is practical, and it's almost surely practical for steel plates which will be electroplated. Use the search engine to browse around for "electrocleaning".
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2022
⇩ Related postings, oldest first ⇩
Q. Hi. I am an environmental engineer and work for a consulting firm. I am trying to find some information for a client who conducts vapor degreasing of stainless steel after it is formed into a product. I am trying to determine when they likely switched from TCE to TCA. I have found information indicating that, as of 1969, TCA was not used for vapor degreasing because suitable stabilizers had not been developed/identified. Does anyone know when these stabilizers were found and when TCA was first used for vapor degreasing? Also, does anyone have specific information regarding the stabilizers historically used in TCA and TCE?
Sarah Levin- Milwaukee, Wisconsin
2000
A. If my understanding is correct, you are predicting when your client changed from TCE to TCA, rather than getting the stabilizers history. I don't think the reason of late emergence of TCA compared with that of TCE was due to the stabilizer. In fact the stabilizers present in industrial TCE and TCA are the same. TCE has a better cleaning ability than TCA. This accounts for its earlier industrial use. However due to health and safety reasons, TCA which has a lower toxicity gradually replaced TCE. Eventually scientists discovered that TCA is ozone-depleting (environmental concern) and TCE came back.
Perhaps both you and I are too young to remember the stories in the '70. Sorry that I can't provide you an answer to your question. Hope that you could have got some idea here for your searching.
Good luck.
- Hong Kong, China
2000
A. Sarah, I do not know but I know who to ask! Call Dow Chemical, they should be able to easily supply at least the information on TCE if not both solvents.
Megan Pellenz
- Syracuse, New York
2000
A. The stabilizers in TCE and TCA are not identical, they are generally similar, and do use some of the same material. TCE will withstand much more water before it degrades than TCA will. Bond strength is higher. Water in hot solvent breaks off the chlorine (s) and forms HCl, or hydrochloric or muriatic acid. When hot, it pits the ----- out of stainless steel.
TCE has better solvency of some soils and operates at a higher temp, so generally cleans better and is easier to trap because it is easier to cool to the condensing point.
About 1983, the US govt changes TCE from a suspected carcinogen to a probable carcinogen. Because of health issues, companies bailed out of TCE in droves.
The Montreal protocol was the kiss of death for the use of TCA because of ozone depletion.
At virtually the same time the Govt says "oops" TCE is not as bad as we thought because the human liver does not react the same as our white mice do.
Therefore, TCE is the degreasing solvent that is mainly used now.
- Navarre, Florida
2000
Q. Sorry to come into this discussion several years down the road. I have a question for Ms. Sarah Levin, Milwaukee, WI. You mention in your 1/19/00 text that you've found information indicating that TCA was not used prior to 1969.
I too have a client that used vapor degreasing in the sixties. We're trying to definitively determine if TCE was essentially the solvent of choice in that decade.
I'd appreciate further conversation. Thanks
- Warner Robins, Georgia, USA
2005
Multiple threads merged: please forgive chronology errors and repetition :-)
Q. I am an environmental consultant and would appreciate knowing of any published information which confirms my general understanding that 1,1,1 TCA came into greater use in vapor degreasing in the late 1970s/early 1980s and was used extensively through the 1980s for this purpose. One of my clients is a retired man who operated a plating business during the 1980s and recalls using only 1,1,1 TCA. We have significant tetrachloroethene (PCE) and trichloroethene (TCE) ground water contamination and only limited impact by 1,1,1 TCA and it's my belief that the PCE and TCE are from prior operations dating back to the 1960s. The old operators are bankrupt, as are their insurance companies, but we may be able to recoup some of our cleanup and study costs from a State fund, if we can make the case that the main impacts (PCE and TCE) are from historical operations.
Sorry for the lengthy post - any help would be much appreciated!
- Princeton, New Jersey
2001
A. PCE has been used for many years to remove wax masking film from plated parts. TCE was a very common vapor degreasing solvent in most plating shops. Conversion from TCE to TCA was the result of USEPA pressures in the early 80's.
Then the Montreal Protocol took effect, with ozone depletion a bigger worry than carcinogens, so TCE is in favor again. EPA decided that a human liver was not the same as a lab rat and that TCE was not that big a problem.
James Watts- Navarre, Florida
2001
Q. James,
Thank you for the response. I was wondering if there is anything published that you may know of regarding the switch to TCA. People in the plating business may know this, but I need to provide some proof of the plating industry trend away from TCE in the late 70s and early 80s.
Thanks again,
- Princeton, New Jersey
2001
A. The company that I worked for switched in 1981. Talk to the good folks at Dow Chemical. They were the largest manufacturer of TCE and did the lion's share of proving that is was not severely carcinogenic to humans, just lab rats.
James Watts- Navarre, Florida
2001
A. "Products Finishing"magazine had an excellent multi-part series on vapor degreasing--a column as I recall--written by J B Durkee. I think it will contain exactly what you're looking for.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2001
Multiple threads merged: please forgive chronology errors and repetition :-)
TCE in aluminum bright dip operation
Q. What is the likelihood that a historic bright dip aluminum operation would utilize trichloroethene (possibly as a cleaning agent)? All suggestions would be appreciated.
Michael Manwaring- Fairfax, Virginia
2002
A. Anything is possible. Since aluminum dust is bad news in a vapor degreaser, I would not give it a very high probability.
James Watts- Navarre, Florida
2002
A. Hi. Bright dipping is usually done in a phosphoric acid / nitric acid mix, but as far as I know it would be one step in an anodizing process, and vapor degreasing is pretty widely used for cleaning aluminum despite the problem Mr. Watts mentions because other cleaners can be problematical. For example, electrocleaning, which is widely used on most other metals, can't be done on aluminum; aluminum will get deeply etched by the strong caustic aqueous cleaners used on other metals; and mixed metal processing in aqueous cleaners causes galvanic corrosion of aluminum. So I think chances are actually pretty good.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Aluminum Fuze Sleeves and TCE
Q. I have two requests. First, I am looking for an expert or someone with knowledge on how aluminum fuze sleeves, which are timing devices for ordnance, were made by companies under contract to the Navy for the Vietnam War. Also, I know that at least 3 or 4 companies made aluminum fuze sleeves for the Navy during this timeframe, but I don't their identities. Second, I am curious if anyone knows whether trichloroethylene (TCE) could have been used in the manufacturing, cleaning or anodizing processes on aluminum fuze sleeves.
Mark BilutMcDermott - Chicago, Illinois, USA
2002
A. TCE was quite likely to have been employed in the finishing of these parts because it was the preferred solvent in vapor degreasers for a couple of decades, and vapor degreasing is good way to start the cleaning and finishing process.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002
Q. This refers to the post by Mr. Peterson. I too have a similar issue and am attempting to definitively confirm the near-exclusive use of TCE in vapor degreasing during the 1960-1970 era.
If you've uncovered supporting data for this matter I'd be interested in discussing.
Thanks
- Warner Robins, Georgia, USA
2005
A. The June 2000 (Volume 1, No. 2) issue of the journal, Environmental Forensics, has two articles that summarize the history of chlorinated solvent use. These can be obtained at:
www.environmentalforensics.org/journal/volume1/number2.htm
Good Luck!
- Princeton, New Jersey
2005
----
Ed. note Dec. 2021: That page no longer works, but those articles are referenced on archive.org's Wayback Machine at
https://web.archive.org/web/20050309200207/www.environmentalforensics.org/journal/volume1/number2.htm
It is available from some of the standard paywalls offering research articles, or if you have good eyes plus infinite patience with dismissing pop-up ads it can be viewed at
www.yumpu.com/en/document/read/39835629/a-history-of-the-production-and-use-of-carbon-tetrachloride-
Multiple threads merged: please forgive chronology errors and repetition :-)
EPA Phase Out of TCE in 1970s
Q. One of my clients recalls switching from TCE to an aqueous product for vapor degreasing as a result of some kind of EPA phase out of TCE in the early 1970s. Does anyone else recall this? Can anyone point me to the regulation that did this? Thank you.
Bret StonePaladin Law Group, LLP - Santa Barbara, California, USA
2005
A. Research decided that TCE was a carcinogen and affected the liver in a study on lab mice. So a lot of the world switched to TCA. Much later, it was decided that TCA was bad for the atmosphere and it was regulated virtually out of use. By a miracle of polemics, it was decided that the original liver damage studies did not apply to humans as the liver functions were slightly different, so TCE became less of a problem. There were games played with "suspected carcinogen" and "probable carcinogen" and "carcinogen".
Talk to Dow Chemical who was in the middle of all of the give and take. They might be willing to provide actual event data and very probably provide their spin on the interpretations.
- Navarre, Florida
2005
A. I'm certainly no expert in US regulations but perhaps it was the 1974 Safe Drinking Water Act which started the ball rolling.
Read this site for more info:
www.epa.gov/safewater/contaminants/dw_contamfs/trichlor.html
- Melbourne, Vic, Australia
2005
----
Ed. note Dec. 2021: That page is no longer available at that location, but can be found courtesy of archive.org's Wayback Machine at
https://web.archive.org/web/20051101131712/www.epa.gov/safewater/contaminants/dw_contamfs/trichlor.html
A. TCE was not banned in the 1970s, and, to the best of my knowledge has never been banned. What did happen is increasingly stringent limits on TCE discharges to air and water to the point that most people found it more practical to switch to other solvents or aqueous cleaners.
Jeffrey Holmes, CEF
Spartanburg, South Carolina
2005
Q. I am looking for articles, guidelines, or standards that directed vapor degreasers using TCE on recommended methods for disposal of spent TCE or TCE sludge.
Jacoby ScherTexas
2006
A. You have no options. You must drum it in legal drums, manifest it properly, ship it via a certified hazardous waste transporter to a certified disposal site. The site is licensed to recover some of it as a cold solvent and they typically burn the rest in a certified furnace. The simplest thing to do is contact a couple of companies that are in this business. Check with the states they operate in or thru to find out their track record on violations.
James WattsNavarre, Florida
2006
Q, A, or Comment on THIS thread -or- Start a NEW Thread