San Juan Generating Station
Toxics Release Inventory
Background
The U.S. Environmental Protection Agency has collected
data from electric utilities, including the San Juan
Generating Station in Waterflow, N.M. The report, known
as the Toxics Release Inventory, details the amount of various
chemicals that are released or contained on site from more
than 600 coal- or oil-fired power stations in the United
States.
The report, required for the first time of electric utilities
in 1998, details the amounts of a number of substances that
are released as the result of burning coal to generate electricity.
Any facility that "manufactures" at least 25,000
pounds of a listed chemical or uses at least 10,000 pounds
of a listed chemical is required to file a TRI report.
2006 TRI Report
Releases of all compounds at San Juan Generating
Station conform to state and federal emission control
regulations, including the federal Clean Water Act, Clean
Air Act and Resource Conservation and Recovery Act.
 2006 TRI data (.pdf)
2005 TRI data (.pdf)
2004 TRI data (.pdf)
2003 TRI data (.pdf)
Almost all of the chemicals San Juan Generating Station reports
are naturally present in coal and the majority of these
chemicals are safely disposed of in the San Juan Coal Mine
or in on-site lined ponds. These chemicals include: arsenic,
barium, beryllium, chromium, cobalt, copper, lead, manganese,
nickel, selenium, zinc, polycyclic aromatic compounds, mercury,
vanadium, benzo (GHI) perylene, dioxin and dioxin-like compounds.
During the combustion of coal, a number of chemical compounds
are formed from naturally occurring chemicals in the coal.
These chemical compounds include sulfur dioxide, hydrochloric
acid, hydrofluoric acid and sulfuric acid. The treatment
of the flue gas by San Juan Generating Station's limestone
scrubber system, in operation at the plant since 1999,
removes a significant portion of these chemical compounds.
The amount of these compounds removed by the system in
2005 is:
| Hydrochloric
acid |
75.5
percent |
| Hydrofluoric
acid |
66.4
percent |
| Sulfuric acid |
62.4
percent |
| Sulfur dioxide |
83.0
percent |
| Mercury |
38.8
percent |
In 2006, 95 percent of the TRI chemicals were managed
on site and did not leave San Juan Generating Station or
the mine property.
Impacts on human health
It is important to keep several factors in mind when viewing
TRI reports. The TRI report does not offer information on
the relative toxicity, exposure or risk associated with
these individual chemicals and makes no assessment of potential
exposure or harm to humans or animals. At coal-fired power
plants, only a limited portion of the compounds listed in
the report are ever released into the air. Others are stored
on-site where there is no impact to land or water.
Analysis by EPA and others have shown that electric power
industry TRI releases do not present a significant public
health concern. A 1998 study published by the EPA indicates
that coal-fired power plant emissions represent no significant
health risks. In a study of 426 coal-fired plants, the EPA
found that the inhalation cancer risks for coal-fired utilities
are less than one in 1 million. (Study of Hazardous Air
Pollutant Emissions from Electric Utility Steam Generating
Units - Final Report to Congress, EPA, February 1998, p.
ES-8.)
George M. Gray, Ph.D., writing in Risk in Perspective for
the Harvard Center for Risk Analysis (April 1999, vol. 7,
issue 2) puts this risk in context. He writes that such
an involuntary risk "is four times smaller than an
individual's lifetime risk of being killed on the ground
by falling aircraft and 100 times less than the risk of
being struck by lightning or drowning in a home bathtub"
(p.5).
More TRI information
Environmental
Protection Agency (epa.gov)
The
National Library of Medicine (nih.gov)
| 
