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Summary:
Section 169A of the Clean Air Act (CAA) sets "as a national goal the prevention
of any future, and the remedying of any existing, impairment to visibility" in
designated "class I areas" (e.g., national parks and wilderness areas). It requires 26
categories of major stationary sources of pollution -- including electric generating
units (EGUs) -- in existence on the date of enactment (1977), but not more than 15
years old as of that date, to install "best available retrofit technology" (BART) if the
state determines the source may reasonably be anticipated to cause or contribute to
any impairment of visibility in any class I area. A key contributor to regional haze
is very fine particles (PM2.5), to which sulfur dioxide (SO2) and nitrogen oxides
(NOx) are important contributors. EGUs are major emitters of SO2 and NOx.
The Environmental Protection Agency (EPA) was directed to issue regulations
to assure that State Implementation Plans (SIPs) required (1) reasonable progress
toward meeting the national goal and (2) compliance with specific provisions,
including the BART requirements. However, EPA delayed issuing regional haze
rules, and in 1990 Congress amended the CAA's visibility requirements. EPA issued
the final regional haze rule on July 1, 1999. Among its provisions, the rule required
"reasonable progress" toward visibility improvement and a state BART
implementation plan. For BART, states could alternatively propose a trading
program -- but only if it achieved greater progress in improving visibility.
The BART requirement's interaction with other air pollution control programs
has become an issue -- most notably its relation to a proposed Clean Air Interstate
Rule (CAIR) to reduce emissions crossing state lines and hindering compliance with
National Ambient Air Quality Standards (NAAQS). CAIR involves controls on SO2
and NOx, focuses on EGUs as the most cost-effective source to control, and proposes
using a trading mechanism to accomplish reductions. At issue is how the CAIR
trading program for EGUs interacts with the BART requirement for EGUs. In 2004
EPA proposed to exempt EGUs subject to the CAIR trading program from the
Section 169A visibility BART program. EPA justified this through an analysis that
looked at class I areas collectively rather than individually. Critics of EPA's proposal
point out that Section 169A specifies protection of individual class I areas and that
BART requirements would be more stringent than CAIR for individual sources; and
they claim that overall, visibility improvements attributable to CAIR would not be
adequate to meet CAA goals.
EPA's effort to meld the visibility program with CAIR is consistent with its
expressed desire to redirect CAA compliance strategies toward a market-oriented,
cap-and-trade program, viewed by many as a more cost-effective approach to
pollution control than direct regulation (such as BART). The Administration has
proposed "Clear Skies" legislation to create a more integrated trading process for
addressing SO2 and NOx emissions from EGUs, but Congress has yet to act. EPA's
proposal represents a regulatory initiative to achieve a partial step in coordinating
certain CAA programs, but it may be that a statutory solution will be necessary. This
report will be updated as events warrant.
