The Congressional Research Service (CRS) is the public policy research arm of Congress. CRS reports are an invaluable resource to environmental legal practitioners, however, their dissemination is only allowed at the discretion of Congress--as a result only select materials are available to the public. Below please find a list of websites that provide copies of CRS reports dealing with various issues in environmental law.
This is only a small selection of available CRS Reports on the Environment.
The Environmental Law Institute (ELI) is "non-partisan research and education center working to strengthen environmental protection by improving law and governance worldwide." The Institutes Research Reports contain "the analysis and conclusions of the policy studies the [ELI] undertakes to improve environmental law." Most of the older reports on this site are available for free (pdf format) from the organization with the proviso that the User provide their email address; other reports are available for purchase for a nominal fee.