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In the United States, the laws and regulations pertaining to the protection of the environment have been enacted by the U.S. Congress. The U.S. Environmental Protection Agency (EPA) is authorized to enforce the environmental laws and to implement the environmental regulations. The United States environmental laws cover various phases of the environment such as water, air, and hazardous waste, where most of the regulations have been based on the risk assessment of the pollutants. The major environmental laws and regulations are briefly listed in the Table Summary of Major Environmental Laws.

The Clean Air Act (CAA) of 1955 and subsequent amendments were established to improve the quality of the air resources in the United States. The CAA amendments of 1990 have provisions for maintenance of ambient air quality to promote and improve public health. Enforcement of regulations is carried out through the use of emission standards on stationary and mobile sources of air pollution that are directed at decreasing the production of air contaminants from various sources. A National Ambient Air Quality Standard (NAAQS) is the maximum permissible concentration of a contaminant in ambient air. Seven classes of air pollutants for which the NAAQS has been established are referred to as criteria pollutants: lead, nitrogen oxides, sulfur oxides, ozone, particulate matter smaller than 10 μm (PM₁₀), hydrocarbons and carbon monoxide. Some pollutants have short-term and long-term standards designed to protect against acute and chronic health effects, respectively. In addition to criteria pollutants, Hazardous Air Pollutants (HAPs) are those pollutants that are known or suspect carcinogens, or may lead to other serious health effects over a longer period of exposure. The main sources of HAPs are industrial and automotive emissions. The CAA amendments of 1990 have provisions for the reduction in emission of HAPs that lead to lower concentrations of HAPs in ambient air.

The CAA amendments of 1990 established a permit program for larger sources of air emissions, where permits are issued by states or by the EPA. Information on the types of pollutants that are emitted, the emission levels, the monitoring of the emissions, and the plans to decrease the emissions is included in the permit. All applicable information on the emissions and legal responsibilities of the business are conveyed by the permit system. The 1990 CAA amendments provide several market-based approaches to businesses to reach their pollution cleanup thresholds such as pollution allowances that can be traded. In addition, economic incentives are provided to businesses to trade the extra credit for operations requiring less cleanup in exchange with the lesser credit given for operations requiring more cleanup.

The CAA aims to reduce emissions from mobile sources such as cars and other vehicles, and to develop cleaner fuels. To maintain higher octane ranking in unleaded gasoline, the refiners have used more volatile fractions in unleaded gasoline formulas, leading to release of volatile organic compounds (VOCs). Under the CAA amendments of 1990, gasoline fuels are required to contain less volatile fractions, to contain oxyfuel compounds (such as alcohol-based oxygenated compounds) for reduced production of carbon monoxide in cold weather, to contain detergents for smoother running of engines, and to contain less sulfur in diesel fuel. The production of cars capable of burning cleaner fuels such as natural gas or alcohol is mandated by the CAA amendments of 1990.

Emission of sulfur dioxide (SO₂) and nitrogen oxides (NO_x) from combustion processes contribute to the formation of acid rain. Most of the sulfur dioxide emitted annually in the United States is produced from the burning of high-sulfur coal by electric utilities, resulting in acid rain with adverse impacts on the environment and public health. Reduction of sulfur dioxide emissions is mandated by the CAA. Pollution allowances (up to prescribed thresholds by EPA) for sulfur dioxide have been established by the EPA for each utility, where allowances may be traded between utilities or within a company. Companies with emissions less than the EPA allowance may trade their excess allowance with companies with allowance deficits, preventing severe hardships to those utilities that that are dependent on high-sulfur coal. The CAA has also set provisions for reduction of NO_x emissions. A market-based approach is employed by the 1990 CAA amendments to eliminate ozone-destroying chemical substances (such as chlorofluorocarbons) that deplete the ozone layer using a phasing-out schedule by terminating the production of these chemicals in accordance with the Montreal Protocol (1989). The recycling of chlorofluorocarbons (CFCs) and the labeling of ozone-friendly substitute chemicals are mandated by the CAA.

Hazardous wastes are wastes that pose a health and safety risk to humans and to the environment. The EPA designates hazardous wastes as wastes which contain components that have one of the four general characteristics of reactivity, corrosivity, ignitability and toxicity, in addition to other EPA classifications of hazardous wastes. The laws and regulations governing the management of hazardous wastes and materials may be divided into two categories: present and future hazardous materials and wastes are regulated under the Resource Conservation and Recovery Act (RCRA), while past and usually abandoned hazardous waste sites are managed under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).

The Oil Pollution Act (1990), or OPA, was established in response to the Exxon Valdez oil spill incident. The Exxon Valdez oil spill (see Figure Exxon Valdez Oil Spill), which occurred in Alaska in 1989, was the largest ever oil spill in the United States, causing major environmental and economic damage in Alaska.

Figure 1: Exxon Valdez Oil Spill Heavy sheens of oil covering large areas of the Prince William Sound, Alaska a few days after the Exxon Valdez oil spill. Source: U.S. National Oceanic and Atmospheric Administration via Wikimedia Commons

The prevention of oil spills in navigable waters and shorelines of the United States is stipulated through the OPA statute. The OPA encompasses oil spill prevention, preparedness, and response performance of industry and the federal government. Incentives are provided to owners and operators for oil spill prevention, enforced by the EPA through the oil spill liability and penalty provisions of the OPA. Oil companies in the United States engage in oil exploration, both offshore and onshore, resulting in accidental releases of crude petroleum into the environment from wells, drilling rigs, offshore platforms and oil tankers. With the exception of the 2010 BP Deepwater Horizon oil spill in the Gulf of Mexico, the number and amount of oil spills have decreased over the past twenty years in the United States despite the increasing demand for oil. This decline has been attributed to the OPA after the Exxon Valdez oil spill incident. The Exxon Valdez oil spill was the largest ever in United States waters until the 2010 BP Deepwater Horizon oil spill (see Figure Deepwater Horizon Oil Spill). BP has been held to be responsible for the Deepwater Horizon oil spill, and has been made accountable for all cleanup costs and other damages by the federal government.

Figure 2: BP Deepwater Horizon Oil Spill The Deep Horizon oil spill in the Gulf of Mexico as seen from space. Source: NASA/GSFC, MODIS Rapid Response AND demis.nl AND FT2, via Wikimedia Commons

Information on all chemical substances and the control of any of these substances which may have an unreasonable health risk has been granted to the EPA through the Toxic Substances Control Act (1976). The manufacturer or the importer of a new chemical must provide information on the identity and hazard, use, production volume and disposal characteristics of the chemical to the EPA. Toxicological tests and unpublished health and safety studies on listed chemicals may be required by the EPA. The EPA may approve, prohibit, or limit the manufacture and sale of the listed chemicals, or may require special labeling. Since some chemical substances such as pesticides, tobacco products, nuclear materials, pharmaceuticals and cosmetics substances are regulated under other acts, they are exempted from TSCA regulations.

The production and distribution of polychlorinated biphenyls (PCBs) are prohibited through TSCA. PCBs are synthetic organic compounds that were manufactured to be used as electrical transformer oil; exposure to PCBs increases the risk of cancer, and may affect the reproductive and nervous systems. The EPA enforces the handling and disposal of PCBs based on established regulations on PCBs, in addition to management of PCBs found at hazardous waste sites. After the amendments of 1986 and 1990, TSCA through the Asbestos Hazard Emergency Response Act requires that all public and commercial buildings identify, control and mitigate the asbestos hazard in these buildings.

Insecticides, fungicides and rodenticides are compounds that are employed to control or eliminate pest populations (pesticides). The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1972 with several subsequent amendments set guidelines for the use of pesticides in the United States. All manufacturers or importers must register their pesticide products with the EPA, where registration is allowed for a pesticide whose application does not have unreasonable adverse effects on the environment. Industries such as the agricultural sector employ pesticides to control vermin and other pests in industrial processes and in the workplace.

A pollution management system with a focus on generating less pollution at the source was established through the Pollution Prevention Act (PPA) of 1990. The pollution prevention hierarchy stipulates that the first step in reducing pollution is to minimize the amount of waste that is generated by all activities and processes, which is referred to as source reduction. When the generation of waste cannot be reduced at the source, then the waste should be recycled in order to decrease pollution. A waste that cannot be reduced at the source or recycled should go through treatment and disposal in an environmentally safe manner. A Pollution Prevention Office has been established by the EPA to promote source reduction as the preferred option in the pollution prevention hierarchy. Pollution prevention is a voluntary measure on the part of the polluting industry rather than a mandatory regulatory control enforced by the EPA and the individual states; industry is only required to file a toxic chemical source reduction and recycling report with EPA every year. Industry is given incentives to institute pollution prevention programs with the aim of realizing the economic benefits of pollution prevention to industry after the implementation of pollution prevention programs.

The Occupational Safety and Hazard Act (OSHA) of 1970 and its amendment of 1990 aim to ensure safe and healthful working conditions for workers through enforcement of standards developed under OSHA, and to provide for research, training and education in the field of occupational safety and health. The standards for occupational health and safety are established by the Occupational Safety and Health Administration and its state partners, which are enforced through inspections of industry and providing guidance on better operating practices. The National Institute for Occupational Safety and Health (NIOSH) was established to recommend occupational safety and health standards based on extensive scientific testing, which are afterwards enforced by OSHA. Those industries which have followed OSHA standards have experienced a decline in overall injury and illness rates, where the costs due to worker injuries, illnesses and compensation associated with occupational safety are a major loss for industry. The OSHA standards for worker health and safety are recommended to be used in conjunction with various industrial pollution prevention programs.

Environmental laws and regulations serve the purpose of limiting the amount of pollution in the environment from anthropogenic sources due to industrial and other economic activities. Environmental regulations are specific to different phases of the environment such as water and air. Government regulations help industry to curtail the environmental impact of pollution, leading to the protection of human health and the environment. Future environmental laws and policy should convey and work in tandem with the efforts of the public and industry for a more sustainable economy and society.

1) For more information on environmental engineering, read Chapter 1 of:

Davis, M.L. & Cornwell, D.A. (2008). Introduction to Environmental Engineering (4^th ed.). New York: McGraw-Hill.

2) For more information about managing environmental resources, read:

LaGrega, M.D., Buckingham, P.L., Evans, J.C., & Environmental Resources Management (2001). Hazardous Waste Management (2^nd ed.). New York: McGraw-Hill.

3) For more information on the U.S. Environmental Protection Agency's laws and regulations, visit:

http://www.epa.gov/lawsregs/