Congress passed the Chemical Diversion and Trafficking Act (CDTA) in 1988 and subsequent amendments in 1993, placing under control 40 chemicals. These laws provide a system of regulatory controls and criminal sanctions to address both domestic and international diversion of important chemicals without interrupting access to chemicals destined for legitimate commerce. The CDTA created two categories for the controlled chemicals, as follows:

List I Chemicals

• Definition from 21 CFR Section 1300.02(b18)
• List of Chemicals from 21 CFR Section 1310.02(a)

List II Chemicals

• Definition from 21 CFR Section 1300.02(b19)
• List of Chemicals from 21 CFR Section 1310.02(b)