EPA’s efforts to regulate greenhouse gases (GHGs) under the Clean Air Act (CAA) have come under attack by some opponents of climate regulation as an “aggressive” and “unprecedented” program of rulemakings. In fact, EPA issued far more regulations to implement the CAA Amendments of 1990.
The attached chart prepared by the Center for Climate Change Law includes side-by-side timelines comparing EPA’s rulemakings during the first four years after the 1990 Amendments were enacted (1991 through 1994) to the four years after EPA’s endangerment finding for GHGs (2010 through 2013).
As the chart illustrates, EPA’s GHG regulations are significantly fewer in number, and much less burdensome from a regulatory perspective, than those issued by EPA to implement the 1990 Amendments.
EPA’s GHG Regulations
In the absence of major climate legislation in Congress, EPA recently issued its first set of GHG regulations under the CAA. The final rules consist of:
(1) the “Tailpipe Rule,” which limits GHG emissions from passenger cars, light-duty trucks, and medium-duty passenger vehicles for model years 2012 through 2016;
(2) the “Timing Rule,” which interprets the CAA to allow regulation of GHG emissions from stationary sources; and
(3) the “Tailoring Rule,” which sets thresholds for GHG emissions from stationary sources. The Tailoring Rule is set to take effect for the country’s largest GHG emitters—power plants, refineries, and cement production facilities—beginning on January 2, 2011. (Smaller sources are exempt from regulation until 2016).
EPA has also laid out its plans for two other GHG regulations it intends to finalize by mid-2012:
(1) limits on GHG emissions from passenger cars, light-duty trucks, and medium-duty passenger vehicles for model years 2017 through 2025; and
(2) limits on GHG emissions from combination tractors (semi trucks that pull trailers), heavy-duty pickup trucks and vans, and vocational vehicles (including buses and refuse or utility trucks) for model years 2014 through 2018.
The 1990 Amendments
By comparison, the 1990 Amendments, which were shepherded through Congress by the George H.W. Bush Administration, required EPA to undertake 120 rulemakings (55 of which had to be completed within the first two years) and prepare 90 reports for presentation to Congress. In order to achieve this directive, EPA was awarded additional funding and hired 200 additional employees.  By November 1993—three years after the 1990 Amendments were signed into law—EPA had issued over 150 rules and guidance documents, accounting for 85% of the total emissions reductions that were expected to result from the fully-implemented 1990 Amendments.
 EPA: Pace of Clean Air Act rulemakings turns heads, draws lawsuits, http://www.eenews.net/public/Greenwire/2010/09/14/2 (Sept. 14, 2010); Texas stays on course toward clash with feds over greenhouse-gas rules, http://texasclimatenews.org/wp/?p=735 (Oct. 6, 2010).
 Note that the timeline of EPA’s regulation of GHGs does not include EPA’s recent regulation of conventional air pollutants under the CAA, such as its Notice of Proposed Rulemaking for the “Transport Rule,” which would require a significant reduction in sulfur dioxide and nitrogen oxide from power plants in the eastern half of the United States, or the revised National Ambient Air Quality Standard for ozone. The CAA lays out timetables requiring EPA to periodically review these and other standards, and update them if necessary to protect public health and welfare.
 See Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards, 75 Fed. Reg. 25,324 (May 7, 2010); Reconsideration of Interpretation of Regulations That Determine Pollutants Covered by Clean Air Act Permitting Programs, 75 Fed. Reg. 17,004 (Apr. 2, 2010); Prevention of Significant Deterioration and Title VI Greenhouse Gas Tailoring Rule, 75 Fed. Reg. 31,514, (June 3, 2010).
 See 2017 and Later Model Year Light Duty Vehicle GHG Emissions and CAFE Standards; Notice of Intent, 75 Fed. Reg. 62,739 (Oct. 13, 2010); Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium and Heavy-Duty Engines and Vehicles, http://www.epa.gov/otaq/climate/regulations/hd-preamble-regs.pdf (Oct. 25, 2010).
 E. Donald Elliott, Lessons From Implementing the 1990 CAA Amendments, Environmental Law Reporter, 40 ELR 10592. See also Office of Air & Radiation, U.S. EPA, Implementation Strategy for the Clean Air Act Amendments of 1990: Update, 1992, available at http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=20011JPT.txt.
 Office of Air & Radiation, U.S. EPA, Implementation Strategy for the Clean Air Act Amendments of 1990: Update, November 1993, available at http://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=00000EK1.txt.