A hazardous waste, as defined by the Resource Conservation and Recovery Act (RCRA), is a waste that appears on any one of four lists of hazardous wastes contained in RCRA or if it exhibits any one of the following characteristics:

• Ignitable - A liquid with a flash point below 140 degrees F; a non-liquid capable of causing fire through friction, absorption of moisture, or spontaneous chemical changes; and/or a flammable compressed gas. An example would be mineral spirits.
• Corrosive - An aqueous-based liquid with a pH less than or equal to 2.0 (strong acid) or a pH great than or equal to 12.5 (strong base). Examples include battery acid and alkaline cleaning solvents.
• Reactive - Wastes that are unstable or undergo violent chemical reactions when combined with water or other materials. An example would be hydrogen sulfide.
• Toxic - A waste that contains metals or organic compounds. An example would be certain hot tank wastes containing high levels of lead, silver, or other metal.
• For more information on hazardous materials and waste, contact the U.S. Environmental Protection Agency or visit http://www.ecy.wa.gov/biblio/92br16.html.

Diisocyanates, found in automotive finishes, are a serious health concern. Auto refinishers who have become sensitized to diisocyanates risk serious harm, if they use diisocyanate-containing materials without adequate protective equipment. In humans, diisocyanates can cause:

• Respiratory sensitization (shortness of breath, wheezing, coughing, or asthmatic reactions)
• Dermal sensitization (skin irritation or allergic reactions)
• Pulmonary toxicity
• Eye irritation
• Lung toxicity
• Cancer

As of January 11, 1999, the U.S. Environmental Protection Agency (EPA) requires that all coatings manufactured in or imported into the United States for auto body refinishing meet specific limits on volatile organic compound (VOC) content. These regulations affect almost all auto body shops in the United States that are not already using low VOC coatings.

Mineral spirits is a commonly used solvent for gun cleaning and parts cleaning because of its ability to quickly dissolve paint, oil, grease, dirt, and grime. Although it is effective for cleaning, mineral spirits raise significant environmental and human health concerns:

• Mineral spirits contain VOCs that contribute to smog formation and may be toxic when inhaled.
• Mineral spirits evaporate quickly, making worker exposure difficult to control.
• Solvent cleaning units can be a facility's greatest source of hazardous waste if not used properly.
• Using mineral solvents can create unnecessary environmental, worker health, and fire liabilities for an auto body shop.
• Minimize costs and regulatory liabilities by switching to less hazardous products, such as aqueous solutions. (Source: U.S. EPA Region 9 Aqueous Parts Cleaning - http://www.epa.gov/region09/cross_pr/p2/autofleet/fleetclean.pdf

Spent gun cleaning and parts washing solvents can become regulated hazardous waste because they exhibit hazardous characteristics such as: corrosivity, low flash points, and/or because they contain more than 10% F-listed solvents such as 1,1,1-trichloroethane or perchloroethylene.

Paint stripping and sanding operations may generate regulated hazardous waste if the paint has a high metals content (this is common in older and military vehicles), and/or if any solvents used in stripping are hazardous (they often contain F-listed solvents such as methylene chloride). These types of wastes may become a hazardous waste and therefore would have to be counted toward an auto body shop's total monthly generation of regulated hazardous waste.

Off-spec or waste paint may become a regulated hazardous waste because of toxicity from heavy metals or ignitability from solvent additives. Water-based paints can be less hazardous and may help reduce VOC emissions.

The EPA has determined that the discharge of commercial wastewater (other than from toilets, showers, etc.) is prohibited without a permit. Septic systems, cesspools, sumps, and floor drains are considered Class V Injection Wells and are regulated by the EPA (40 CFR Parts 144 and 146).

When operated correctly, high-volume, low-pressure (HVLP) spray guns have notably higher transfer efficiencies (60-70%) than conventional spray guns (20-30%). This means that with HVLP spray guns, more paint ends up on the car and less is lost as overspray. This efficiency is a great benefit to painters, who have less contact with toxic paint components, and the shop, which saves many dollars in paint costs.

If an auto body shop has to manage refrigerants, keep the following in mind:

• It is illegal to vent chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs) into the atmosphere.
• Federal regulations require that CFC-12 and HCFCs be recycled. However, it is not illegal to use in-stock, recycled, or remanufactured stocks of these chemicals.
• All facilities servicing motor vehicle air conditioning systems must certify to EPA that they have acquired and are properly using approved CFC or HCFC recycling equipment.
• EPA requires that facilities with refrigerant recycling equipment keep records of the name and address of the facility to which any refrigerant is sent for reclamation. These records must be kept for three years. The facility must also have records showing that all persons authorized to operate any recycling equipment are currently certified.

For more information on CFCs, refer to the Clean Air Act of 1990 - http://www.epa.gov/oar/oaqps/peg_caa/pegcaain.htm