The depainting dilemma

The Depainting Dilemma

Environmental regulations are forcing paint facilities to switch products

By Shanin C. Pepple

March 1998

With environmental regulations on paint strippers looming in the near future, paint facilities across the country are having to search for alternatives. Some facilities have chosen to bite the bullet and make the switch to environmentally-friendly strippers, but others, satisfied with their current selection, are waiting until they are forced to make the change. Regardless of which path facilities have chosen, one fact remains, the aircraft painting and stripping industry will never be the same.

One of the concerns in the aviation industry is the prevalent use of hazardous air pollutants (HAPs) in paint strippers. The Environmental Protection Agency (EPA) created the Aerospace National Emission Standards on Hazardous Air Pollutants (NESHAP), which places restrictions on the use of HAPs in the industry by September of this year. Methylene chloride, one of these HAPs, is used extensively by paint facilities to strip aircraft. Those paint facilities who use methylene chloride, and who have used it for years, praise it for its speed and efficiency.

In addition to the NESHAP, methylene chloride is regulated by the Occupational Safety and Health Administration (OSHA). Under the OSHA Final Rule, employers must ensure that no worker is exposed to methylene chloride in excess of 25 parts per million (ppm) as an eight-hour time weighted average (TWA). The previous exposure level was 500 ppm. The rule also changes the current short-term exposure limit from 2,000 ppm to 125 ppm as a 15-minute TWA. The initial OSHA Final Rule took effect April 10, 1997.

After protest from the industry, OSHA has extended its compliance date for general aviation depainting operations that have more than 20 employees while they evaluate the effects the regulations will have on the general aviation painting industry. This means that employers engaged in general aviation stripping have until Aug. 31, 1998, to comply with the requirement to use respiratory protection whenever an employee's exposure to methylene chloride exceeds the new, lower, eight-hour TWA permissible exposure limit (PEL). OSHA is further extending the requirement to implement engineering controls to achieve the lower eight-hour TWA PEL and short term exposure limit(STEL) until Dec. 10, 1998.

Despite the increased regulations on using methylene chloride, many painting facilities are still reluctant to change — until they have to. While many have switched to products that are composed of less methylene chloride, they don't want to completely switch to environmentally-friendly strippers. However, that doesn't mean they aren't experimenting with these environmentally-friendly, HAP-free strippers.

In fact, larger paint facilities are testing new environmentally-friendly strippers weekly. And that's why some aren't ready to make the switch — they are unimpressed with the alternatives to methylene chloride. They've tried chemical strippers made with water, formic acids, benzyl alcohol, peroxide, etc. They've even tried dry strippers. Those facilities with the time will try almost anything a sales person from a chemical manufacturer offers them. Sometimes the results are promising and sometimes they are discouraging. One thing is for sure: nothing, so far, has been found to directly replace methylene chloride.

Duncan Aviation in Lincoln, NE, is one paint facility that is searching for a replacement for methylene chloride-based strippers. "We're still actively looking for something that will work," says Dan Svoboda, paint production team leader of Duncan. "The other day, we used four different types of strippers on one aircraft. One was 36 percent (HAP), one was 19 percent (HAP), and two were non-HAP strippers."