The United States Environmental Protection Agency (EPA) maintains and approves test methods, which are approved procedures for measuring the presence and concentration of physical, chemical and biological contaminants; evaluating properties, such as toxic properties, of chemical substances; or measuring the effects of substances under various conditions. The methods in the Agency index are known as EPA Methods.^[1][2] There are other types of methods such as the ASTM and United States Pharmacopeia, but the EPA Methods are developed through a regulatory process involving public notice, comment and revision and are legally binding whereas ASTM methods are developed through a consensus process and compliance is voluntary.^[3][4][5][6]

Mission of EPA

The mission of EPA is to protect human health and the environment. EPA works to ensure that:

• Americans have clean air, land and water;
• National efforts to reduce environmental risks are based on the best available scientific information;
• Federal laws protecting human health and the environment are administered and enforced fairly, effectively and as Congress intended;
• Environmental stewardship is integral to U.S. policies concerning natural resources, human health, economic growth, energy, transportation, agriculture, industry, and international trade, and these factors are similarly considered in establishing environmental policy;
• All parts of society--communities, individuals, businesses, and state, local and tribal governments--have access to accurate information sufficient to effectively participate in managing human health and environmental risks;
• Contaminated lands and toxic sites are cleaned up by potentially responsible parties and revitalized; and
• Chemicals in the marketplace are reviewed for safety.^[7]

${\displaystyle {\begin{matrix}{\ce ((P2O5}+3H2O->2H3PO4))\\{\ce {2KNO3->[{\text{heat))]{2KNO2}+O2))\\{\ce ((Al4C3}+12H2O->{4Al(OH)3}+3CH4))\\{\ce {C))_{n}{\ce {H))_{2n}+{\frac {3n}{2)){\ce {O2->[{\text{heat))]))\ n{\ce {CO2))+n{\ce {H2O))\end{matrix))}$

Nomenclature

The method numbers generally range from 1 to 9000 and may have modification letters appended to the end, signifying a newer version of the method has been released. Some ranges of numbers appear to be organized with intention, for example methods 1-99 being air methods or the 7000s being for hazardous waste.^[8] Others number ranges, however, seem to only contain random methods, like the 300 and 400 series both being for wet chemistry methods.^[9]

Searchable databases

Since the EPA methods are created by different regulatory departments within the EPA, finding methods on the EPA website itself can be challenging.^[1] To make finding methods easier, some organizations have created method search databases that organize all the methods into one place and link to actual test methods. Some allow searching by method number, analyte, or other keywords in the method.^[10][11]