WATERLOO -- The air-conditioning that saves Iowans from long, muggy summers doesn't come cheap. And American's growing appetite for such amenities and rising population -- combined with a rise in the price in natural gas -- makes the market ripe for new coal power plants.

When one was proposed in Waterloo's back yard, hopes of economic stimulation voiced at public hearings were tempered with warnings of negative effects on residents' health.

The good news is something experts can agree on: The $1.3 billion facility, a 750-megawatt, coal-fired plant planned by LS Power and its affiliate, Elk Run Energy Associates, will be much cleaner than yesteryear's model. Indeed, the most egregious pollution offenders among the nation's power plants are coal facilities several decades old.

"The project that we're proposing, it's not your grandfather's coal plant. It's a totally new technology," project manager Mark Milburn said.

Experts also agree coal power plants -- no matter what generation -- emit pollutants that harm human health. That's why federal regulations are in place.

Agreement ends, however, when the question arises about the severity of consequences caused by a coal power plant.

Determining the direct health effects of any one power plant is difficult, said Tom Newton, division director of environmental health at the Iowa Department of Natural Resources. As such, the agency does not keep those kinds of statistics.

"Some of the conditions that you may see associated with large industrial facilities, such as hospital room visits for asthmatics, (isn't) a reportable disease. So it's difficult to make an association between a pollutant and the illness," Newton said. "I think we know that emissions at various levels can cause a response."

The point at which people get sick is the measuring stick for federal oversight. Newton said regulations take into account those levels and officials cautiously drop emissions even lower.

Because any proposed power plant must pass state and federal Environmental Protection Agency regulations, Newton said, the public will be safe if a plant is built in the area.

"The bottom line is that, if the EPA and state of Iowa deemed that our plant or any other plant would not be safe for the environment or for human health, then they wouldn't give us a permit and wouldn't allow us to operate," Milburn said.

Keep in mind, he added, the majority of air pollution doesn't come from coal power plants. That distinction falls on cars.

Corn processing, grain processing and cement plants join coal plants in the top 10 polluting facilities in the state, according to DNR statistics. The No. 1 and 2 individual polluters by far, however, are large coal power plants in Council Bluffs and Sergeant Bluff.

Coal power plants contribute a sizable chunk of the nation's air pollution. Skies became cleaner when power plants shut down during a 2003 blackout in the Northeast U.S., according to a University of Maryland study. And they are the largest source of man-made mercury in the country.

'Tolerable' levels

Jonathan Levy is an associate professor of environmental health and risk assessment at the Harvard School of Public Health. He said a study he helped conduct showed coal plants, even with the latest control technology, will make people sick and cause premature deaths when air pollution levels meet or exceed federal safety standards.

That is because the EPA sets air quality standards to a "tolerable" level, Levy said, not one at which no one gets sick. He added ample corresponding information exists about the evidence of health effects below national ambient air quality standards.

A study by Levy and colleagues was used in a 2003 court challenge of a pair of proposed 615-megawatt coal-fired power plants in Oak Creek, Wis. The plants are scheduled to go online in 2009-10. They are, individually, "fairly comparable" to the power plant proposed in Waterloo, Levy said. LS Power has not yet filed permits with the state, so specifics on the Waterloo plant's emissions aren't available.

The study found chronic respiratory disease, like asthma, cardiovascular disease and premature death, were all more likely to occur because of pollution from the new plants, even when federal regulations were met.

The researchers concluded the two power plants would produce 26 premature deaths, 2,000 asthma attacks, 350 emergency room visits, 26 hospital admissions, 26,000 minor restricted activity days and $188 million in impact on public health.

While there is plenty of data on the health effects of older coal power plants, the study Levy's school conducted is one of the few to examine the impact of plants using the latest technology.

Milburn noted rebuttal testimony in the court case criticized and attempted to debunk the Harvard study. Those testifying against the plaintiffs said the assumption and methods used were inaccurate. The courts eventually ruled the proposed plants were safe for human health and the environment and allowed construction.

Among the counterclaims was one that the study, which examined fine particulate matter -- the type of pollution most likely to cause adverse human health effects -- did not account for the large variety of particles in existence. Those include some from dirtier sources, like diesel trucks.

The testimony maintained pollutants in the study -- even those that didn't come from coal power -- were incorrectly attributed to the plants.

Levy stands by his findings. He emphasized the data used in the study "was really standing on the shoulders" of health evidence compiled by the EPA and other researchers.

"I think we saw, as in any place else, the health effects range from severe, but less frequent -- such as premature death -- to respiratory symptoms, which are more frequent, but less severe," he said.

The study showed the lives of people, usually the elderly and sick, would be cut short by months because of fine particulate matter exposure. Trying to predict life expectancy beyond that time frame is difficult, Levy said.

In addition, the study found those who lived closest to the plant would face an increased chance of severe health effects, while more people farther away would become sick.

In Wisconsin, however, large population centers, Milwaukee and Chicago, respectively, are north and south of the plant. The population of Oak Creek is a little more than 30,000.

"For the Wisconsin power plants, only a relatively small fraction of those premature deaths occurred, say, within five miles of the plant," Levy said.

Clearing the air

As part of the federal law that requires plants to use the "best available technology," the proposed Waterloo facility will capture 90 percent of mercury emissions by using a halogenated activated carbon injection system.

Milburn said that will result in "the lowest mercury emissions rate, probably, that has ever been built."

John Thompson is director of the Clean Air Task Force's coal transition program. He also appeared as a witness for the opposition during the permitting process for an LS Power plant in Texas,

He says one of the main drawbacks to traditional coal power plants is mercury -- a neurotoxin with no half-life -- and its storage.

"The problem with a conventional coal plant on the mercury side is that even if you're capturing 95 percent of the mercury, you're taking that mercury and you're dispersing it in a mountain of sludge each year. The chances of it re-emerging in the biosphere is a lot higher than in technology like coal gasification," Johnson said.

The coal waste, or sludge, is either sent to a landfill or sold for another use, like wallboard or road construction.

Coal gasification uses an integrated gasification combined-cycle, a process that breaks coal down into a gas and results in a cleaner fuel. The new technology is more expensive than its coal-fired counterpart, and Milburn argues it is not yet viable economically.

Most mercury concerns should be alleviated by the Clean Air Mercury Act, which will reduce utility emissions of mercury from 48 tons per year to 15 tons -- a nearly 70 percent reduction -- by 2018, said Catharine Fitzsimmons, the Iowa DNR's bureau chief of air quality.

The act, announced last year, was heavily criticized by opponents for its cap-and-trade system, which places a national cap on emissions but allows older and higher polluting plants to trade mercury to newer, lower polluting plants.

The law regulates how much mercury can leave smoke stacks, but Fitzsimmons said the lack of an ambient air quality standard for mercury, a measurement at ground level where people breathe air, constitutes a definite hole in state and federal regulations. She said mercury is one of close to 200 air pollutants any facility can emit for which no ambient air quality standard exists.

"It's one of those funny things. You can have limits on how the equipment operates, but if you don't go ahead and look at what those emissions are on the ground level, then you really don't have the full story," she said.

Contact Jens Manuel Krogstad at (319) 291-1580 or jens.krogstad@wcfcourier.com.