Bad Stuff Out
We recently had a request from a customer who wanted to know how he could be sure that our solvent remover contained no chromates, since this seemed to be a requirement of NADCAP. We advised him that one could not have a product listed on the QPL if it contained chromates, but he needed something in writing directly addressing the question. This got us to thinking
about how the qualification criteria has changed over the years.
Possibly the first substance to be forbidden was asbestos, as a component of developers.
The next qualification change concerned aerosol propellants, when chlorofluorocarbons (CFCs), such as Freon® were found to contribute to depleting the ozone layer. They were banned as an aerosol propellant in 1979, now 34 years ago! Although this
is now a long time ago, it is not unusual to still see a note that “This product contains no CFCs”.
Following this, it was found that other chemical compounds, described as Ozone Layer Depleting Substances (OLDS) also contributed to the depletion of the ozone layer, and these bit the dust and were prohibited in QPL qualified products. These included 1-1-1 trichloroethane, trichloroethylene, perchlorethane, and carbon tetrachloride. Next came hexavalent chromium, a
chemical widely used as an efficient corrosion inhibitor, but which also had undesirable health effects, some of which were portrayed in the movie “Erin Brockovich”. We were sure that these prohibitions were part of AMS-2644, but a review of the latest edition found only a mention of asbestos. Further inquiry revealed that somehow the listing of these prohibitions had apparently “fallen through the cracks”. This will eventually work its way back into the specification, but in the meantime, users of QPL approved penetrant materials can be assured that they do not contain any of these substances.