Asphalt is a petroleum-based substance used in road construction as an ingredient of asphalt concrete, which accounts for 80% of all asphalt used in the U.S. The other 20% is used for the production of asphalt roofing shingles. Up until the 1980s, such roofing shingles were likely to contain asbestos.
Under the National Emissions Standards for Hazardous Air Pollutants (NESHAP), asbestos-containing, asphalt roofing materials are classified as a Category I substance; such materials are less likely to become friable, and also include asbestos gaskets and flooring. Asbestos was commonly used in roofing shingles in order to make them flame-retardant and increase the tensile strength and durability of the substance.
Asphalt used for roads and curbs may also contain asbestos. This was commonly done in the 1960s and early 1970s in some states that salted their highways during the winter. This was in order to make the base of the roads less susceptible to damage from brine, as well as strengthen the overall road material. In the state of New Hampshire , the lower levels of the road material contained 1.5% asbestos; this was discontinued in May of 1979. According to that state’s Department of Environmental Services, such asbestos-containing asphalt pavement is not a health hazard as long as it is intact and "not abraded or ground up.
Asbestos-containing materials (ACMs) fall under NESHAP rules if (A) there is more than 5580 square feet of ACMs to be removed, and (B) it will create more than 160 square feet of friable ACM (meaning that the material will release asbestos fibers into the air as it is damaged). Buildings that are slated for demolition or renovations are required to have an inspection done prior to the start of work under NESHAP regulations regarding asbestos. Private, single-family dwellings are exempt from the federal rules, however, several states do have regulations pertaining to asbestos removal from such structures.
While owners of commercial and rental property have no choice in the matter under federal law, private homeowners should consult with the department of health and/or environmental issues before attempting to remove any ACMs from their properties. Even if there are no state laws about such work within the boundaries of the property itself, ACMs that are removed from private property are subject to NESHAP and federal environmental laws. Ssuch waste must be transported in plastic bags no thinner than 6 mils, must be clearly labeled as asbestos waste, sealed with duct tape, and can only be legally disposed of at authorized toxic waste sites.