EPA Memorandums and Alternative Testing Procedures (ATPs)

In 2007, the EPA released a memorandum (PDF) on the flexibility to modify Clean Water Act Methods without prior approval by the EPA. This flexibility did not apply to drinking water and is very limited in scope. An Alternate Test Procedure (ATP), in contrast, must receive approval by the EPA prior to its use. In addition, ATPs enable laboratories to use a method that is not in 40 CFR 136 or a modification that falls outside the scope of method flexibility. For more information on ATPs or how to obtain one, please see the EPA’s website.

In addition to releasing ATPs to the public, the EPA issues memorandums. They have been used to share a wide variety of information, sometimes clarifying method/program requirements and, other times, informing the public about acceptable method modifications.

The following is not a complete list. If you are aware of any pertinent items that are missing, please email health.mnelap@state.mn.us. MNELAP will continue updating this webpage.

EPA Memorandums and Alternative Testing Procedures (ATPs)

• Satisfying the 16-hour Sample Hold Time for Acidified Metals Samples (PDF)

• The use of hydrogen as an alternate carrier gas in drinking water compliance methods (PDF)