Carcinogens In Grass Smoke Ewu Researcher Details Harmful Chemicals
FOR THE RECORD: 11-12-96 Due to an Eastern Washington University researcher’s error, grass smoke samples reported as collected in 1993 were actually gathered in 1991. The Spokesman-Review reported Saturday on harmful chemicals found in the smoke from Kentucky bluegrass fields in the Spokane area.
An Eastern Washington University chemist’s studies show grass smoke contains cancer-causing chemicals.
It also contains many dangerous compounds that laboratory tests indicate can cause skin irritation, breathing problems, tumors and birth defects, the study found.
Professor Jeffrey Corkill’s work - the first of its kind in the nation - shows grass smoke isn’t simply harmless soot and steam as some Kentucky bluegrass growers have claimed.
In a lawsuit filed in August in Whitman County, several bluegrass farmers unsuccessfully challenged the Washington state Department of Ecology’s plan to curb burning. The growers said there was no “generally accepted scientific evidence linking grass field smoke to (an) adverse impact on public health.”
But Corkill’s research indicates the chemicals in grass smoke are also found in cigarettes, forest fires and in wood stove smoke, a major pollutant in Spokane during the winter.
Corkill’s work is pioneering because he’s the first to analyze what’s in smoke from local bluegrass fields, said Washington state’s senior toxicologist in Olympia.
His work rebuts claims by the grass seed industry that grass smoke is less harmful than other combustion products, said Dr. Harriett Ammann of the Washington Department of Health.
“It’s the first study that specifically looks at grass smoke. Growers have been arguing it’s different from cigarette or wood smoke. These results show that just isn’t so,” Ammann said.
Ammann said Corkill’s research also bolsters the need for a burning ban, which the Department of Ecology plans to adopt next month.
Ecology’s new regulations would douse most bluegrass field burning by 1998.
A spokeswoman for the Intermountain Grass Growers Association did not return several calls Friday asking for comment on Corkill’s report.
The industry’s view has been that grass smoke is harmless. Farmers annually burn fields in Washington and Idaho to stimulate crop growth.
“The smoke intrusion into Spokane isn’t going to hurt anybody,” said John Cornwall, president of the 450-member growers’ association, last year in a meeting with Gov. Mike Lowry.
Corkill’s studies of grass smoke samples col lected since 1993 show it contains both irritating phenols and hazardous polyaromatic hydrocarbons PAH for short. They can cause both acute eye and skin irritation and chronic lung disease.
“They are either carcinogens or mild irritants,” Corkill told the Spokane County Air Pollution Authority board on Thursday.
Before Corkill’s study, researchers thought phenols were only found in wood smoke, said Grant Pfeifer, Ecology’s top air quality official in Eastern Washington.
“This is the first time they’ve been found in grass smoke,” Pfeifer said.
Two of the substances Corkill measured in grass smoke, benzopyrene and chrysene, are the most dangerous. They are found in the atmosphere as the product of incomplete combustion.
Benzopyrene is a known human carcinogen, Ammann said.
It’s been called the chemical trigger in lung cancers among laborers, including coke oven and roofing tar workers. It’s also present in cigarette smoke.
PAH is thought to be among the “likely actors” in lung cancers from cigarette smoking, Ammann said. Benzopyrene causes cancers and mutations at levels as low as 70 nanograms per cubic meter of air, according to Corkill’s research. A nanogram is a billionth of a gram.
This spring, when no field burning was taking place, “background” PAH levels he measured in Spokane’s air were a low 10 nanograms per cubic meter, Corkill found.
By contrast, PAH levels soared to 2,670 nanograms during one test at Elder and Marshall roads during field burning in September 1993. The sample site was immediately downwind from several large burning fields.
“This work shows the PAHs are high above background during field burning. That’s a hazardous amount,” Ammann said.
Even short-term exposure to these chemicals has been shown to cause health problems - including death in vulnerable people with asthma and other lung diseases, she said.
“Being indoors does not significantly reduce a person’s exposure,” professor Jane Koenig of the University of Washington said in recent court testimony supporting Ecology’s burning ban.
In his most recent grass smoke samples taken last month, the total concentrations of small particles containing the hazardous chemicals was about 30 percent of the total smoke, according to Corkill’s report.
His work eventually may help explain why Spokane’s asthma rate is 20 times higher than normal.
, DataTimes ILLUSTRATION: Photo Graphic: Dangerous chemicals found in smoke