DISCLAIMER: These classification structures, and the classification rules they contain, are works-in-progress as part of an academic research effort at Stanford University. Further, the text version of 40 CFR that is searchable on this site was downloaded in January of 2001 for research purposes only.

**THIS SITE DOES NOT CONTAIN
**THE CURRENT VERSION OF 40 CFR.

For counsel regarding environmental compliance, consult an attorney.

Index to the National Primary Drinking Water Regulations
(An alphabetical index of terms in 40 CFR 141)

Index for Drinking Water Information
(An alphabetical index of terms in a corpus of material dealing with drinking water)

The Periodic Table of Elements
(A classification of terms in 40 CFR according to the Periodic Table of the Elements)

On the Topics of Regulation, Pollution, and Waste
(A classification of terms in 40 CFR on the topics of regulation, pollution, and waste)

EPA List of Extremely Hazardous Substances
(A classification of terms in 40 CFR according to the EPA's list of Extremely Hazardous Substances)

The Fifty U.S. States
(A classification of 40 CFR according to state names. Use this hierarchy to find locations in 40 CFR where a specific state is discussed. N.B. - this is being applied to Federal Regulations, you will not find State Regulations through this classification hierarchy.)