Researching Environmental Law: Legislative History

Legislative history documents may be used:

1. To aid a court in its interpretation of statutory language, but only if
   1. The statutory language is unclear on its face,
   2. No statutory canons exist to guide the court in its interpretation, and
   3. There are no existing judicial or federal agency interpretations of the statutory language
2. To track a pending bill as it moves through Congress
3. To provide background or historical information for research

The more detail you can begin with the easier your research often becomes. Some indexes and search services may ask you to use specific features of a piece of legislation to help find it. The more information you have, the more you can be sure you're finding what you need. Having these details can make your online or print searches much more precise, saving time and creating better research. When discussing US federal laws, you want to know:

1. Public Law number. This is often abbreviated PL or Pub. L. No. The format is PL 91-190: the first number (91) is the Congress number and the second number (190) means it was the 190th bill to pass during the 91st Congress (1969-1971). 
2. Location in the U.S. Statutes at Large. A public law is first printed as a slip, similar to a slip opinion, and is then printed in a collection called the Statutes at Large. The citation format is: 83 Stat. 852 (1969). This is similar to a judicial opinion - the public law printed at 83 Stat. 852 (1969) is in the 83rd volume of the Statutes at Large starting on page 852, and it was passed in 1969. The Statutes at Large are organized chronologically before being codified by subject matter in the United States Code. 
3. The number of the House or Senate Bill and the Congress in which the bill was enacted. This will also help ensure you're finding the right document. House bills are abbreviated H.R. and Senate bills are abbreviated S.; they are numbered in the order they are introduced in each Congress. They may be formatted in slightly different ways. 91 S. 1075 and S. 1075, 91st Cong. (1st Sess. 1969) both cite to the same bill, the National Environmental Policy Act (NEPA) - introduced as the 1,075th Senate bill in the 91st Congress. Note that the second cite is in accordance with Bluebook Rule 13.
4. The date of enactment. Having the date will only help you. Acts may have the same name that can throw you off. 

Popular Name Table

A useful tool for finding this information is the Popular Name Table, which lists acts by their well known names. If you want to research the Clean Air Act but do not know the statutory provision or the public law number, then you would start with the popular name table. A version of one of these tables will accompany virtually ever version of the U.S.C., whether it's on a commercial service on in print. 

Historical Notes

At the end of a legislative provision in the U.S.C., there will be notes that give the history of the bill that will give you the public law number and the Statutes at Large citation. When on commercial services like Westlaw, be sure to explore the other content associated with the statute as it could include important historical information. In print publications of the statute, online through the U.S. Government Publishing Office, and some other commercial services, the historical information will follow the text of the statute. This may include notes on amendments. Compare how the first section of the Clean Air Act, 42 U.S.C. 7401, looks in the U.S.C. with the Westlaw version (known as the U.S.C.A., US Code Annotated).