Making tiny specialty steel tubes for use in products like heart stents takes a lot of precision, but the manufacturing process generates a lot of friction.
For years, two narrow tube manufacturers in Pennsylvania have used trichloroethylene (TCE) in their manufacturing process as a solvent during the degreasing phase after the lubricated tubes are drawn down to smaller and smaller sizes, often with a wall thickness of just a few thousandths of an inch. The highly toxic solvent was leaking into the air, however, causing health concerns among residents and the Pennsylvania Department of Environmental Protection (DEP).
Superior Tube Co. Inc. and Accellent Inc., both in Collegeville, near Philadelphia, have invested considerable time and money in research and development to rectify the situation. No fines or penalties have been imposed on either company, the DEP said.
Superior Tube completed reformulation and degreaser removal projects that are expected to reduce TCE emissions by more than 50 percent this year. The company also plans to eliminate TCE from its manufacturing process and replace it with n-propyl bromide (nPB), an alternative approved by the U.S. Environmental Protection Agency. Unlike TCE, nPB is not considered an air toxic.
Accellent chose to install two carbon absorber units to control TCE emissions from its large degreasers. The company began operating its first unit last October. While the absorber equipment manufacturer guarantees emission reductions of 35 percent, the DEP believes that is a very conservative estimate. Emissions reductions of 90 percent or greater can result from this type of installation, according to the DEP.
The state agency is already seeing results. Recent data from a stationary air monitor near Collegeville in Evansburg State Park shows that levels of airborne TCE are diminishing, with many days registering no measurable levels. That trend is expected to continue, given the companies' voluntary efforts to reduce emissions, the DEP said.
Tony Jost, Superior Tube's president and chief executive officer, said his company has been working to reduce environmental emissions for six years. "It's consistent with our environmental policy of being a good corporate and community citizen."
Jost said his company made emission reductions in 1999 and again in 2002 and continued to investigate further measures by teaming with its sister company in Britain and with sources in the solvent industry. "There is no shortage of experts to work with," he said. "There were multiple things we explored using. The challenge was finding something that you could use."
The company notified customers about the potential for processing changes and assured them that the new methods would still meet their quality demands, Jost said. "We had to make sure we maintained the quality that our customers have come to expect from us. We've studied the project for a long time and (have) gotten as confident as we can without compromising the quality of our products."
It's important to maintain metallurgical properties and cleanliness since the tubes that Superior makes must be highly pure, he said. In addition to medical applications like heart stents, end-use applications for Superior's products are in the aerospace and nuclear fields.
"Our markets have no tolerance for any issues," Jost said, declining to say how much Superior spent on research and development and equipment modifications necessary to use nPB, noting only that it was "a significant investment" for the privately held company.
Engineering consultant Matson & Associates Inc., State College, Pa., said in a report that nPB is more expensive than TCE, pegging the cost of nPB at roughly $3 a pound vs. about 70 cents a pound for TCE for large industrial users, although most nPB users see a 5- to 20-percent reduction in solvent purchases after switching.
Lynda Rebarchak, the state DEP's community relations coordinator, couldn't say whether Superior's or Accellent's approach to reduce TCE emissions was the better method. "We're technology neutral when it comes to these things," she said. "It's up to the companies to figure out the best way for the process they do and the different contracts they have, whether that's FDA or military."
Superior had been under more pressure from local residents after news that two small TCE spills occurred, Rebarchak said. "Accellent was not under as much pressure, but now with Superior switching altogether residents are now saying they'd like to see Accellent switch, too."
According to the EPA, TCE exposure is associated with several types of cancer and with health effects ranging from headaches to liver damage. The DEP found TCE air levels in the Collegeville area were significantly higher than elsewhere in the state, putting area residents at a greater health risk.