A generator of a hazardous waste must conduct a hazardous waste determination in order to ensure its wastes are properly managed.  This determination may be conducted using solely generator knowledge of the waste and the process of generation or it may include the testing of a representative sample of the waste using either an approved test method (40 CFR 261, subpart C) or an equivalent test method approved by USEPA (40 CFR 260.21).  Both test methods require the generator to collect and submit for analysis a representative sample of the waste.

The term “representative sample” as used by USEPA is defined at 40 CFR 260.10:

Representative sample means a sample of a universe or whole (e.g., waste pile, lagoon, ground water) which can be expected to exhibit the average properties of the universe or whole.

Sample methods that can be used to obtain a representative sample are listed in Appendix I to Part 261.  At §261.20(c) it indicates that any of the applicable sample methods specified in Appendix I will be considered a representative sample as that term is defined at §260.10.  And, in a comment to 261.20(c):

…a person who desires to employ an alternative sampling method is not required to demonstrate the equivalency of his method under the procedures set forth in §§260.20 and 260.21.

In short, you may use an alternative sampling method (one not identified in Appendix I) and you can do so without having to demonstrate its equivalency; but, no matter what method is used, all samples obtained for the purpose of the determining the characteristic of a hazardous waste for the hazardous waste determination must be a representative sample, which brings us back to the definition in §260.10.

Q:  Where can I learn how to obtain a representative sample?

A: ASTM D5956, Standard Guide for Sampling Strategies for Heterogeneous Wastes