QUINCY - The state Pollution Control Hearings Board ruled Wednesday that the Department of Ecology correctly calculated the impact of emissions from backup generators at Microsoft's data center in Quincy.

The memorandum opinion issued by the board does not constitute the board's final decision and is not an appealable order.

The appeal to the board came from a group of Quincy residents concerned about the impact of emissions from backup diesel generators on people's health. The group argued that emissions estimates Microsoft used to support its health risk analysis was flawed.

The board found that "the emissions estimates used to support the health risk analysis and the analysis of compliance with emissions standards were validly derived and support Ecology's permit decision."

The board found changes to the permit language were required.

The limits on how long Microsoft can operate the generators should be "modified to more clearly match the modeling assumptions that were made when calculating emissions," the board found.

The board also found that changes were required to address testing and maintenance to ensure compliance with emission standards.

The same group that appealed the state Department of Ecology's approval of permits for Microsoft's data center has outstanding appeals for other data centers.

"I think this is ... for lack of a better term, a good precedent that has been set by this decision," said Pat Boss, of the Port of Quincy.

Quincy is a city with high power redundancy, which makes it almost impossible for the entire city to lose power, he said. That means the backup generators would rarely have to be used.

"Our Department of Ecology is probably one of the most rigorous and thorough agencies that there is when it comes to these decisions," he said. "They've looked at this several times and have concluded that the generators are not a problem."

Patricia Martin, a member of the group that filed the appeal, was disappointed by the board's decision, but sees the changes to the permit language in the board's ruling as a victory.

"On the one hand I'm disappointed in the decision, but on the other hand we did get some transparency issues which will be a benefit to the community and we would not have had them without the appeal," she said.

Microsoft's testing and maintenance records will be submitted to the Department of Ecology and be available to the public, she said.

"There will be greater accountability on these engine runs," she said.