These methods are approved alternatives to the methods required by 40 CFR Parts 60, 61 and 63. As such, they may be used to determine compliance with the requirements of these Parts without further EPA approval.
The methods in this category are not likely to be technically supported by EPA staff and are more likely to change based on the review of additional validation studies or on public comment prior to adoption as a Federal reference method.
In 2000, the Office of the Federal Register (OFR) and the Government Printing Office created the Electronic Code of Federal Regulations (e-CFR) prototype. The OFR updates the e-CFR prototype on a frequent basis, providing the public with up-to-date access.