Department of Toxic Substances Control

DTSC Online Reference Library

DTSC Online Reference Library (DORY) The Department of Toxic Substances Control is providing access to documents that have been written in response to questions regarding hazardous waste identification, classification, and recycling. Most of these letters were written prior to 2006.

NOTE: The reader is cautioned that each document was written in response to a specific situation. Subtle differences in the facts may result in a different interpretation. In addition, the reader is cautioned that when statutes or regulations change, past interpretations may no longer be valid.

Please note that descriptions of letters that match your search may have unusual characters in them. This is a result of the optical character recognition performed on the original files, and not an error in the results. The following is an example of unusual characters in the description:

image showing unusual characters in a paragraph
Figure: unusual characters in the paragraph shown above.

Search Tips:
  • Think simpler. For example, if you are looking for letters on pharmaceuticals, try pharmaceutical instead. Removing plurality often yields results.
  • Consider similar terms, such as drug, medication, or medicine.
  • Try single words, rather than multiple words at the same time. This may improve the number of documents that are found. Multiple words works best with the full text search, not with the keyword search.
  • If you want an exact match, enclose multiple words in double quotations, such as "oil filter".
  • If searching for a legal citation containing special characters, such as 261.4(b), enclose it in quotes: "261.4(b)".
  • For legal citations, such as 261.4(b), enclose it in quotes: "261.4(b)".
  • You may include or exclude words or phrases by adding a + or - before the terms or phrases. You can use double quotations with inclusion or exclusion, but do not include the + or - in the quotations.