Revised January 29, 2004
- On December 15, 2003 the Environmental Protection Agency (EPA) proposed
a rule to permanently cap and reduce mercury emissions from power plants
for the first time ever.
- In a separate but closely related action known as the “Interstate
Air Quality Rule”, EPA will propose a regulation to improve air quality in the
Eastern United States. This proposal would address windblown air pollution by requiring
states to reduce sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions.
States could comply with these requirements through a cap and trade system based
on the successful Acid Rain Trading Program.
- EPA believes it makes sense to address mercury, SO2 and NOx emissions
simultaneously. These rules would protect public health and the environment
without interfering with the steady flow of affordable energy for
American consumers and businesses.
- The health benefits of addressing mercury, SO2, and NOx in an integrated
fashion are dramatic. EPA expects this suite of actions to reduce
the number of asthma attacks and heart attacks around the country by lowering
the levels of fine particles and ground-level ozone in the air. By reducing mercury
levels, it also would reduce potential risks for pregnant women and young
children who consume certain fish from local streams and lakes.
- EPA is proposing two alternatives for controlling emissions of mercury
from utilities and will take comment on the alternatives before taking
final action. The alternatives include:
- proposed rule requiring utilities to install
controls known as “ maximum achievable control technologies” (MACT)
under section 112 of the Clean Air Act. If implemented, this proposal
would reduce nationwide emissions of mercury by 14 tons (29 percent) by
the end of 2007; and
- proposed rule establishing “standards of performance” limiting
mercury emissions from new and existing utilities. This proposal, under
section 111 of the Clean Air Act, would create a market based “cap-andtrade” program
that, if implemented, would reduce nationwide utility emissions of
mercury in two distinct phases. In the first phase, due by
2010, emissions will be reduced by taking advantage “co-benefit” controls –
that is mercury reductions achieved by reducing SO2, and NOx.
emissions. When fully implemented, mercury emissions will be reduced
by 33 tons (69 percent).
EPA’s modeling projects that applying this approach to controlling
emissions from utilities will yield much greater health and environmental
benefits than could be achieved through a traditional MACT standard.
This modeling is based on the successful Acid Rain Trading Program,
which resulted in more emissions reductions than required, sooner
required, and at less cost to the consumer than expected with a very
rate of compliance.
- EPA also is proposing to revise its December 2000 finding that it is “
appropriate and necessary” to regulate utility hazardous air emissions
using the MACT standards provisions (section 112) of the Clean
Air Act. This action would give EPA the flexibility to consider a more efficient
and more cost effective way to control mercury emissions.
- EPA will take comment on this
action for 60 days after publication in the Federal
Register. EPA intends to hold two public hearings on
this proposed rule.
- This mercury proposal coupled with the proposed Interstate Air Quality
for the largest single industry investment in any
clean air program in the past
Mercury Emissions – Both Naturally Occurring
and Man-made Sources
- Mercury is a toxic, persistent pollutant that accumulates in the food
fuel-fired utilities are the largest source of
human-generated mercury emissions
in the United States.
- Concentrations of mercury in the air
are usually low and of little direct concern.
However, atmospheric mercury falls to Earth
through rain or snow and enters
lakes, rivers and estuaries. Once there, it
can transform to its most toxic form,
methylmercury, and accumulate in fish and animal
- Americans are exposed to mercury primarily by eating contaminated fish.
Because the developing fetus is the most sensitive to the toxic
mercury, women of childbearing age are regarded
as the population of greatest
concern. Children who are exposed to low
concentrations of methylmercury
prenatally are at increased risk of poor
performance on neurobehavioral tasks,
such as those measuring attention, fine motor
function, language skills, visualspatial
abilities, and verbal memory.
- The proposed standards of performance establish a cap-and-trade system
mercury based on EPA’s proven Acid Rain Program. The Acid Rain Program
produced remarkable and demonstrable
results, reducing SO2 emissions faster
and at far lower costs than anticipated,
and resulting in wide-ranging
- Under the cap-and-trade approach
proposed in this rulemaking, EPA would
allocate to each state specified amounts of emission “allowances” for
The states would allocate those allowances
to utilities, which would trade them.
A utility must hold sufficient allowances
to cover its emissions each year, so
limited number of allowances ensures
that the required reductions are achieved.
- The mandatory emissions caps in the proposed standards of performance,
coupled with significant automatic penalties for noncompliance,
that human health and environmental
goals would be achieved and sustained.
the same time, stringent emissions
monitoring and reporting requirements
flexibility possible. The flexibility
of allowance trading creates financial
for utilities to look for new and
low-cost ways to reduce emissions and improve
the effectiveness of pollution control
- The Clean Air Act Amendments of 1990 required EPA to complete two studies
related to mercury and report their findings to Congress. One
focused on the health and environmental impacts
of mercury, the other focused on hazardous air
emissions, including mercury, from utilities.
- In a pair of 1994 legal settlements, EPA
agreed to revised deadlines to complete
these studies. EPA also agreed
to make a determination about
regulation was appropriate
and necessary and, if necessary
propose a MACT
standard to reduce hazardous
air emissions from coal and
- The “Mercury Study” analyzed mercury emissions from utilities
industrial sources, the health
and environmental impacts
of those emissions and
available control technologies.
EPA issued the Mercury Study
in December 1997.
- In the “Utility Report” to Congress, issued in February
1998, EPA analyzed
emissions of toxic air
pollutants, including mercury,
- The 1994 agreements were modified several times. In 1998, EPA agreed
its regulatory determination
by December 2000; to
propose regulations by
December 15, 2003; and
to finalize regulations
by December 15,
- In December 2000, EPA announced that it would regulate
emissions of mercury
and other air toxics
from coal- and oil-fired
the Clean Air Act.
While this announcement
did find that it was necessary
appropriate to control
mercury emissions from
utilities, it did not
those levels of control
would be. To do so
would have prejudged
the outcome of
the Agency’s rulemaking
- Under the MACT provisions of the Clean Air Act, sources commonly are
given only three years to comply with emission reduction
requirements. For an industry like power generation, which has many facilities
requiring controls, the MACT approach raises concerns about how quickly
new control technologies could be put into place. Further,
the short compliance window would preclude the effective
use of developing technologies. Relative to an allowance trading system, the
MACT also restricts the options and incentives for power plants
to achieve lowcost reductions. These higher costs could lead
to increased electricity prices.
- MACT standards also generally require industries
to meet limits that are currently
by a number of
would like to
of achieving reductions
those being achieved
- Currently, there are no adequately demonstrated
control technologies specifically
designed to reduce
NOx also are
some cases, at
reducing mercury emissions
This is another
reason EPA believes
to couple the
Air Quality Rule.
The degree of
removal depends in
of coal being
- EPA’s goal is to provide the highest degree of mercury control possible
involve a range
that will encourage
to reduce emissions
which would occur
from the implementation
of a traditional
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