A tentative agreement has been reached at defusing more than a year of discord between Cottage Grove residents and 3M Co. over plans to burn hazardous waste from other firms at its plant near the city.

Under the deal, outlined Wednesday night at a special City Council meeting at Cottage Grove Middle School attended by about 150 people, 3M will install and pay for an air-monitoring system near the incinerator for the next three years.

The company also agreed to limits on the types of wastes that will be burned at the massive incinerator, which now takes all hazardous wastes produced by the company in North America.

The incinerator has been in operation for 40 years, but 3M is seeking permission from the Minnesota Pollution Control Agency (MPCA) to allow it to take waste from other companies. Because the company has been reducing its own amount of hazardous waste, it needs the extra supply to burn at the incinerator -- which runs around the clock -- to avoid having to use more costly natural gas.

The expanded permit has drawn vocal opposition over the content of the new hazardous waste that would be brought in. The company has said the new waste would be as closely monitored as waste produced in-house.

"If 3M didn't care -- if it truly didn't care, we wouldn't have a tentative agreement," Mayor Myron Bailey told the crowd.

The air-monitoring system will provide a baseline against which air quality at the incinerator can be measured. Bailey said he expects the air quality to be better than that in the Twin Cities.

The city has hired a consulting environmental engineer, Thomas Henning of Short Elliot Hendrickson of Minneapolis, to supervise the air monitoring.

Along with the monitoring, which will cost 3M $60,000 a year, the company agreed to four conditions: Not accepting compensation from other companies to burn the waste; accepting only waste from other companies with high energy content (which excludes lead); a limit on the amount of non-3M wastes based on their energy content, and restricting wastes from law enforcement agencies (such as waste cleaned up from methamphetamine labs) to be only from Minnesota.

Officials from 3M were not at the meeting, but in a statement the company said the voluntary monitoring "will confirm the incinerator at 3M Cottage Grove does not negatively impact our community's air quality."

There were plenty of 3M rank-and-file workers at Wednesday's meeting. Workers have responded to opponents more visibly in recent weeks, and many carried signs saying "3M CG = Good Jobs." The Cottage Grove plant employs 714 people, more than half of them union members, who have made the incinerator a jobs issue.

Members of the Coalition of Concerned Cottage Grove Citizens, the chief opponents to the expanded permit, opted not to participate in the meeting.

Michael Sandusky, director of the MPCA's Environmental Outcomes Division, said the permit proposal entails three separate permits, which will also be reviewed by the U.S. Environmental Protection Agency. There will be opportunities for written comments, and a public hearing will be held in Cottage Grove, he said.

The timeline likely will be decided by the end of the year. "As you might suspect, we are as interested in bringing this to a conclusion as anyone else," he said.

As he has said before, Bailey told the crowd the city's power to regulate the incinerator is severely limited. "We may not all agree, but I do believe we've come to a good conclusion," he said.

Jim Anderson • 651-735-0999