Asphalt plants, or more accurately asphalt pavement mixing facilities, are industrial operations that mix liquid asphalt binder (also called asphalt cement) with crushed rock, gravel, and sand (collectively called ag-gregates) to make pavement. Asphalt binder, the glue that binds the aggregates together, is one of many distilled products obtained from the oil refining pro-cess. Similar to other refined oils, such as lubricating oils, asphalt binder is processed to meet defined stan-dards. Some mixes also require additives, which can range from chemicals that improve mix performance to natural fibers that strength specialty mixes. The use and storage of these materials is carefully monitored and regulated.
Asphalt pavement mixing facilities are well-regulated by federal and state environmental agencies, and they employ multiple emission control systems. The small amount of emissions released from these control systems are closely monitored to ensure they stay well below any permitted level set by the U.S. Environmental Protection Agency (EPA) and other regulators to ensure that they pose no health or environmental risk to nearby communities.
In fact, over a decade ago, the EPA reviewed emis-sions from asphalt plants and determined that such facilities are not a major source of air pollution and were subsequently delisted by the agency！Subse-quent studies by various regulatory agencies have verified that emissions from asphalt pavement mixing facilities do not present an environmental or public health hazard.