On Tuesday, 3M was given permission to burn hazardous waste from outside sources, ending a three-year battle with citizens who worried about potential pollution.

The citizens' advisory board of the Minnesota Pollution Control Agency reissued air and hazardous-waste permits that will allow the Maplewood-based mega-corporation to burn solvents from others, including law enforcement agencies, in Cottage Grove at its only incinerator.

"We're obviously very pleased with the outcome," said Vicky Batroot, site supervisor for 3M at Cottage Grove. She said she believed the MPCA staff did a good job of summarizing the pertinent facts about the permit application.

A group of concerned citizens from Cottage Grove attended hearings and meetings for years -- armed with calculations and impassioned testimony -- as they tried to stop 3M from getting an amended permit. Opponents said that they wanted the state to order 3M to prepare an Environmental Assessment Worksheet to show there would be no adverse effects with the change.

"Three and a half years has been a long time for both the MPCA and the citizens," said Fred Luden, who represented the Coalition of Concerned Cottage Grove Citizens, and who testified Tuesday before the citizens board.

A former site supervisor for 3M's operation in Cottage Grove, Luden and others had circulated a petition that asked the MPCA to deny the permit, saying it would only bring more pollution to the area.

3M officials say that's not the case, and state experts agreed.

"Our position is that there will be, from this change, no measurable increase in emissions," Batroot said. "And we will show that with our air monitoring."

Batroot said in recent years, as 3M cut its use of solvents and increased its ability to recycle, the company saw a big drop in liquid solvent waste sent to the incinerator. That meant 3M needed more nonrenewable fuel oil and natural gas to maintain the incinerator's temperature.

To reduce outside expenditures, 3M applied for an amendment to its original permit so it could burn solvent waste from outside 3M to fuel its incinerator.

With the amended permit approved Tuesday, Batroot said, 3M will save from $1 million to $2 million a year in natural-gas costs, depending on the price.

"It will save enough natural gas to heat 2,000 homes for a Minnesota winter," she said.

Cottage Grove owns monitoring and testing equipment to keep tabs on local air quality and the city has employed a third-party environmental consultant to manage the monitoring. 3M supports the monitoring financially and has equipment on its property.

The permit sets maximums for the amount of non-3M solvent waste that can be burned, Batroot said that shouldn't be an issue.

"We will burn only enough non-3M waste as we need, and not a pound more, in order to supplement our fuel and not have to burn natural gas and fuel oil," she said.

Early on, area residents express worries about increasing truck traffic. Currently, 125 trucks a day, on average, drive onto the 3M site. The change is estimated to add one or two trucks a day, she said.

Minnesota law enforcement agencies are also pleased with the change, which means they'll no longer have to truck confiscated controlled substances out of state under armed guard for incineration. Some agencies have paid up to $2,000 for a 55-gallon drum to be taken out of state for incineration, Batroot said.

There is no permitted incineration method for such substances currently in Minnesota.

The materials could include methamphetamine, pharmaceuticals and other confiscated law enforcement waste, but will amount to less than 1/100th of 1 percent of the total volume of material incinerated, Batroot said.

Joy Powell • 651-925-5038