Leaders of several state environmental groups are worried that one of Iowa's largest air polluters is deceiving state air monitors.

    Workers at the Grain Processing Corp. facility in Muscatine acknowledged last fall that they switch from burning high-sulfur coal to a low-sulfur variety when the wind blows toward a nearby sulfur-dioxide monitor, an Iowa Department of Natural Resources complaint investigation shows.

The Grain Processing Corp. facility in Muscatine, Iowa is being investigated for attempting to deceive state air monitors. (Photo: Muscatine First / Flickr)

    "When the wind blows toward the local SO2 monitoring station, (plant operators) switch from 'regular' to low-sulfur coal," DNR senior environmental specialist Kurt Levetzow wrote in a letter to Grain Processing Corp. last November. "When we questioned the operators, they admitted to doing just this."

    The issue is important, according to several environmental experts, because switching coal only when the wind blows toward the monitors can make emissions appear artificially low. State and federal agencies use the monitoring data to inform policy and enforcement decisions.

    "That kind of thing violates the principles of what an ambient monitor should tell us," said Susan Heathcote, a member of the Iowa Environmental Protection Commission, which sets state environmental policy. "It needs to have an accurate picture of what's going into the air during normal conditions."

    But Janet Sichterman, a spokeswoman for the company, said in a statement that the company burns low-sulfur coal at times "to maintain good air quality in Muscatine" by reducing sulfur emissions when the wind blows toward the populated areas around the city.

    The facility is located less than one-half mile from Garfield Elementary School, which ranked as having worse air than about 93 percent of U.S. schools in a study conducted last year by USA Today. The study found that children nationwide were breathing toxic and potentially cancer-causing chemicals because of industrial pollution near schools.

    Sulfur dioxide can cause respiratory problems and is a primary component of acid rain.

    "The question that has to be asked is, by switching coal, are they barely keeping (sulfur dioxide) under the nonattainment level?" said Lee Searles, air quality program director for the Iowa Environmental Council.

    The Muscatine area, home to Grain Processing Corp. and several other large polluters, was declared to be in nonattainment of federal sulfur dioxide standards in the early 1990s.

    Violating federal standards can require expensive changes to reduce emissions. The region has also violated standards for fine particle pollution, according to the U.S. Environmental Protection Agency.

    Brian Hutchins, head of compliance for the DNR's air quality bureau, said Grain Processing's coal swaps are not illegal, nor do they violate the company's permits. However, he called the practice of switching coal unusual.

    "I don't know that it's common," Hutchins said. "This is really the only instance I'm aware of with someone trying to take some measures to prevent, perhaps, an exceedance at the monitor."

    The company said a study conducted several years ago showed the facility's sulfur dioxide emissions could combine with those of several nearby facilities, but only when the wind was blowing from the south - or toward the monitor.

    "If certain meteorological conditions occur, GPC will voluntarily switch coal to prevent any possible adverse impact on the ground-level concentrations of sulfur dioxide," the statement from Sichterman said.

    Low-sulfur coal can cost more to burn and require expensive plant modifications.

    A Des Moines Register investigation published last month showed state and federal efforts to monitor Iowa's air quality are often incomplete, relying on industry data and imprecise methods for measuring emissions. Experts say the Grain Processing case highlights the inexact nature of the air monitoring system designed to keep Iowa's air safe to breathe.

    "We have so few monitors anyway, and if they're manipulating the results, people ought to know that," said Neila Seaman, director of the Iowa chapter of the Sierra Club.

    The state operates a network of more than 30 ambient air monitors that are designed to test air quality in population centers and industrial areas. Readings from those monitors help officials determine whether the air is clean enough to meet federal public health standards.

    The Grain Processing facility, which burns coal to power its grain processing operations, emitted more sulfur dioxide in 2007 than all but three facilities in Iowa, according to a Register analysis of state emissions records.

    The DNR began its investigation after a complaint was brought last October by union workers who had been locked out of the facility following failed contract negotiations, Levetzow said.

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