Additional restrictions on hard chrome plating
June, 2012: EPA is working on proposed new limits for hexavalent chromium air emissions, which should be announced in the Federal Register during the 2012 year.
In addition to air contaminants, the EPA also regulates wastewater (under the Clean Water Act), groundwater contamination, and disposal of hazardous waste. All of these have an important impact on hard chrome plating operations. Platers must now ensure that:
- Cr6+-contaminated wastewater such as rinse water is properly treated before discharge to the sewer
- The plating plant is constructed to prevent spills that could cause groundwater contamination (which has happened beneath many older chrome plating plants)
- The plating solution or sludge and any Cr6+-contaminated materials such as masking materials, air filters, and solids and liquids from air-handling systems are recycled or properly disposed of.
Nickel – next on the hit list?
The Clean Air Act currently requires the EPA to control 188 hazardous air pollutants, also known as toxic air pollutants or air toxics, which are believed to cause adverse environmental and ecological effects. Of these pollutants, the so-called EPA Toxic 17 have been singled out as toxics of the greatest potential concern. This list of targeted materials includes compounds of the four metals – lead, mercury, cadmium and chromium, whose use in products has been strictly limited by the new European ELV and RoHS directives – but also includes nickel and its compounds.
Inhaled nickel dust is classified by the EPA as a class A human carcinogen, largely based on studies of nickel refinery workers. While soluble nickel salts such as those used in plating have not yet been evaluated for potential carcinogenicity by the EPA, they have already been declared as carcinogens by the State of California, which now regulates all new nickel plating installations – both electroless and electrolytic – in the state. In the EU, a number of restrictive controls have been instituted on nickel emissions, both into the air and the water supply. Furthermore, nickel is known to cause a wide range of allergies. For all these reasons, nickel and its salts are likely to become increasingly regulated worldwide.