Environmental protection concerns span a wide variety of issues, including clean air, water quality, chemical security, and environmental aspects of other major issue areas such as energy, transportation, and defense. This issue brief provides an overview of key environmental issues receiving attention in the 109th Congress. The attention to Hurricanes Katrina and Rita involved a number of environmental concerns, including legislative proposals on matters such as emergency waivers of environmental requirements. A number of environmental measures have been the subject of congressional activity, some of them as part of comprehensive bills and laws on broader subjects such as energy and transportation. On August 8, 2005, President Bush signed P.L. 109-58 (H.R. 6), the Energy Policy Act of 2005, an omnibus energy package that contains numerous environmentally related provisions. Perhaps the most controversial include a renewable fuel standard and streamlined environmental permitting. On August 10, 2005, the President signed the transportation reauthorization bill, P.L. 109-59. This law, the Safe, Accountable, Flexible and Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), contains various environmental provisions. Appropriations for the Environmental Protection Agency (EPA) affect many of the programs and issues discussed in this issue brief, and the adequacy of EPAâ€TMs funding has been of perennial interest in Congress. In the second session, the House passed on May 18, 2006, the FY2007 Interior, Environment, and Related Agencies appropriations bill (H.R. 5386). This bill would provide $7.58 billion for EPA, an increase above the request of $7.32 billion but less than the FY2006 appropriation of $7.71 billion. The second session also has begun consideration of FY2007 defense authorization (H.R. 5122 and S. 2766) and appropriations legislation (H.R. 5385), which include funding for cleanup and other environmental activities on military lands. None of these bills include exemptions from air quality and environmental cleanup requirements that DOD requested. Early in 2005, the Senate Environment and Public Works Committee held hearings and scheduled markup of S.131, the Clear Skies Act. However, the bill failed on a tie vote on March 9, 2005, owing to the contentious nature of the debate over whether clean air regulation would be made more effective or weakened by the legislation and whether it should include the greenhouse gas carbon dioxide. The Administration continues to advocate passage of the clear skies bill. As bills receive floor action, they will be listed at the end of this report in Table 1, which briefly describes each bill and its current status. The sections on specific issues contain references to more detailed CRS reports. [Note: This issue brief treats mainly pollution-related matters; for natural resource management issues, see CRS Report RL32699, Natural Resources: Selected Issues for the 109th Congress.]