By Saul Hubbard, The Register-Guard

Critics blasted Seneca Sustainable Energy’s efforts to alter the air pollutant permit for its wood-burning electricity plant off Highway 99 at a public hearing Wednesday evening.

Loosening the 21/2-year-old plant’s emission limits for certain pollutants represents a broken promise, they argued, and means another hit to air quality in west Eugene.

“Seneca has consistently failed to meet its limits” for those pollutants, said Carla Hervert, who lives close to the plant. “So now they want to increase them.”

But backers said the plant is “the cleanest of its kind in the nation” and represents only a small fraction of pollution in the metropolitan area.

Dave Hauser, president of the Eugene Area Chamber of Commerce, said the “slight change” requested in the plant’s permit is based on a better understanding of actual emissions at the facility, after repeated tests and two-plus years of operating.

Under the proposed permit change, Seneca is also proposing to lower its emission limits for several other pollutants, Hauser and others pointed out.

At issue is the particulate matter released by the plant. Seneca is seeking to increase its annual emission threshold for particulates from 14 tons to 16 tons, which would push the plant from a “minor” to a “major” source of pollutants in the Eugene-Springfield area under the federal Clean Air Act.

The particulates generated by the plant have a diameter of 2.5 micro­meters or less — known as PM 2.5.

The presence of particulates decrease air quality and can aggravate asthma, bronchitis and other chronic lung diseases, decrease lung function and aggravate heart disease. That in turn can mean more emergency room visits, hospital stays and premature death of health-sensitive people, including the very young and very old, according to the Environmental Protection Agency.

Because of the proposed increase to its particulates threshold, Seneca has purchased so-called offsets from International Paper in Springfield of 34 tons a year — or double the amount legally required. The offsets refer to particulates that International Paper has the authority to emit but is not emitting.

Another more minor change Seneca is seeking is an increase in its carbon monoxide limit from 105 pounds to 149 pounds an hour on an eight-hour average. Its 30-day and annual carbon monoxide emission limits would remain unchanged.

Finally, the company wants to increase its limit on hydrogen chloride emissions, while reducing its thresholds on other hazardous pollutants such as formaldehyde, acrolein and styrene.

Despite some ongoing public opposition to the plant, representatives of the regulating Lane Regional Air Protection Agency said Wednesday that, if the changes proposed by Seneca meet legal requirements under the Clean Air Act, as they appear to, the agency cannot deny the permit.

What the air protection agency does have some say over during the new permit process is the type and frequency of tests at the facility to ensure that Seneca does not exceed its particulate emission thresholds, LRAPA permit writer Max Hueftle said.

Lisa Arkin, executive director of Eugene-based Beyond Toxics, wasn’t satisfied with that response.

“You didn’t give the public any way to be a meaningful participant in this process,” she said to LRAPA representatives. “Look at what the result of you hiding behind the rules might be.”

Ruth Duemler of Eugene said she doesn’t understand why purchasing offsets from a Springfield company could give Seneca more freedom to pollute in west Eugene.

“Why should we allow one area in our community to be polluting by getting offsets from some other company all the way across town?” she asked.

Todd Sloan defended Seneca, praising the operations of the company’s sawmill, which is located next to its burner.

“This is a good, clean mill, the best I know,” he said. “Let’s do the best we can with what we got and quit complaining.”

Ingrid Kessler, a Eugene resident, said she believed after seeing LRAPA’s presentation that “science was on (Seneca’s) side.”

Burning wood to create electricity “is not perfect,” she said. “There’s no form of energy generation that is.”

LRAPA will accept additional public comments through Nov. 22. It could then issue a new permit early next year.

Seneca sells its power to the Eugene Water & Electric Board.

No Seneca representatives were present at Wednesday’s hearing. Company officials have previously said the plant hasn’t exceeded its current particulate limits in recent tests, but that the increase is needed because the plant is close enough to the threshold that an unknown variable in the burning process could push it over that limit.