Consensus on Mercury Recommendations
By Russ Harding
Mackinac Center for Public Policy
Posted September 16, 2005
Gov. Jennifer Granholm established the Michigan Mercury
Electric Utility Workgroup two years ago to fulfill a campaign
promise to phase out mercury emissions from coal-fired power
plants. The workgroup was directed "to strive for recommendations
based on workgroup consensus" and to produce a report
in six months. Two years later, the workgroup has published
its report with little consensus on what should be done.
Perhaps it is unsurprising that a committee composed
of government officials, scientists, utility representatives
and staff from interest groups would have trouble agreeing.
But in fact, the problem is not merely political; it is
fundamental, involving uncertainty on such basic issues
as the scientific justification for state mercury-emission
controls and the controls' likely effects. This inconclusiveness,
particularly given the cost of the extreme reductions
that some have recommended to the governor, explains why
the state shouldn’t adopt state regulations and should
instead monitor the progress of a new federal mercury-reduction
Mercury is a heavy metal found in rocks and in the by-products
of industrial processes. Mercury created by human activities
— called "anthropogenic" mercury — is estimated
to account for up to two-thirds of the mercury in the
environment. Coal-fired utility boilers are the single
largest source of anthropogenic mercury in the United
The primary concern about mercury is its potential effect
on human health. Mercury in aquatic ecosystems can be
methylated by microorganisms into an organic form that
can accumulate in fish and animal tissue. Methylated mercury,
in turn, is a neurotoxicant that at elevated exposure
levels can cause an increased risk to a developing fetus.
From this consideration, two questions arise: Is environmental
mercury a health problem in Michigan, and if so, would
the stringent regulations recommended by some in the workgroup
be an effective way to address the risk?
The primary human exposure to mercury is from consuming
fish. The two best-known epidemiological studies that
measure the effect on fetuses and newborns of heightened
exposure to mercury through maternal consumption of ocean
fish are inconclusive, with one suggesting a negative
effect and one suggesting no effect. There remains a great
deal of controversy in the public health community about
the advisability of fish consumption in the potential
presence of mercury, since the risk of mercury exposure
must be weighed against the positive health benefits of
In the Great Lakes, levels of mercury continue to decline.
Mercury concentrations in Great Lakes-region bald eagle
feathers fell approximately 20 percent between 1985 and
2000 — a telling measure, since the eagles are at the
top of the Great Lakes food chain and their primary diet
is fish. Nor is the case likely to be different with humans.
The panfish that Michiganians typically catch and prepare
from the lakes are not the riskier types of high-food-chain
fish — swordfish, tuna — that contain higher levels of
bioaccumulated mercury and become the subject of scientific
In addition to scientific questions about the risk posed
by mercury, there are also questions about the effects
of a proposal that some members of the workgroup have
recommended: mandating a 90 percent reduction in mercury
emissions from Michigan’s coal-fired utilities.
In theory, this sounds like a huge impact on the presence
of mercury, but in practice, it is not clear how large
the effect would be. Computer modeling by the U.S. Environmental
Protection Agency indicates that despite the amount of
mercury emitted by Michigan's coal-fired power plants,
they are responsible for less than 2 percent of the mercury
deposits in Northern Michigan and for less than 5 percent
of the deposits in central and Southern Michigan.
One reason these percentages are so low is that much
of the smokestack mercury from coal-fired power plants
is believed to be oxidized before falling to earth, so
that it is changed to a form that does not bioaccumulate
in fish. Another reason is that the mercury emissions
generated by Michigan power plants often do not land inside
the state, but are blown outside the state’s boundaries.
In fact, much of the mercury in Michigan’s atmosphere
comes from international sources, and most anthropogenic
mercury deposition in Michigan comes from sources outside
the state. Thus, the proposed Michigan regulations would
probably fail to address key sources of the state’s mercury.
The effectiveness of the proposed state regulations are
also unclear given the federal government’s new mercury-control
program. Instituted in March, the regulations establish
a strict baseline emissions standard. Compliance with
a second and even tougher standard may be met either by
adopting new technologies, or by buying credits sold at
market prices by companies that have lowered mercury emissions
even further than required under the law.
Such an approach not only reduces the costs of cutting
emissions, but is effective; a similar trading system
has cut national sulfur dioxide emissions by 41 percent
since 1980. The federal program for mercury is projected
to reduce nationwide mercury deposition by approximately
20 percent by 2010, and by 70 percent by 2018.
Given the mobility of the mercury emissions across state
and national borders, the federal proposal makes more
sense than a state regulation. True, the projected national
reductions could be uneven; the Granholm administration
has even joined a lawsuit against the federal government
arguing that because some utilities will buy emissions
credits and thus avoid the strictest emission standard,
reductions in Michigan would be insufficient even if they
were dramatically reduced nationwide.
But in fact, no one knows how specific utilities will
respond to the new federal system and how their actions
will affect local mercury levels. Adding state regulations
to the mix might even create perverse incentives in some
cases to move new economic activity and power generation
outside of Michigan, thereby increasing production at
power plants whose mercury discharge is more likely to
fall in Michigan and ultimately curtailing some of the
projected effectiveness of state regulation.
And the proposed state regulations will not be cheap.
An analysis found in the Mercury Electric Utility Workgroup’s
own report indicates that more stringent controls in Michigan
would increase homeowners’ electricity costs by $59 million
annually and commercial users' costs by $153 million annually,
due to the high capital cost of additional smokestack
controls. Increased electricity costs in the state — which
are already higher than most of the Midwest — would worsen
Michigan’s uncompetitive business climate.
Gov. Granholm should reject suggestions to add further
mandatory controls on Michigan coal-fired power plants.
Great Lakes mercury levels are declining, and to the extent
that mercury remains a human health threat in Michigan,
the federal program is a more sensible first step in improving
it. It would be a big mistake indeed to implement state
mercury regulations whose necessity and effectiveness
would be uncertain, but whose costs to Michigan's economy
would be high.