Editors' Summary: A generator may use its knowledge of processes and materials to determine whether a waste must be managed as hazardous waste. This is generally referred to as using "process" or "generator" knowledge to characterize a waste. A generator may determine how the waste should be treated and disposed under the RCRA land disposal restrictions by using "acceptable" knowledge. Using process knowledge to characterize a waste and acceptable knowledge to determine a waste's fate under the land disposal restrictions is less time-consuming and more cost efficient than testing. However, the regulations provide only general statements as to what is sufficient to document waste characterization or treatment and disposal based on a generator's knowledge. Further, courts have not yet dealt with sufficient number of cases to help define a legal standard for process or acceptable knowledge. This paper reviews the regulations governing the use of process knowledge under 40 C.F.R. § 262.11 and acceptable knowledge under 40 C.F.R. § 268.7. The limited case law is also reviewed. The paper outlines some of the risks a generator may encounter suggests some alternatives that may help lessen these risks, and proposes methods to define a workable standard for relying on process or acceptable knowledge.