DataCenterKnowledge has a post about Washington State's Department of Ecology studying the environmental impact of Data Center Diesel Generator operation in Quincy, WA.

Quincy Generator Cluster Draws Scrutiny
September 13th, 2010 : Rich Miller

An aerial view of the Microsoft data center in Quincy, Washington

Economic development officials love clusters of huge Internet data centers. But environmental officials are less enthused about large clusters of diesel generators. The town of Quincy, Washington has both, serving as home to major data centers for Microsoft, Yahoo and Intuit (with another project from Sabey Corp. on the way).

As much as the big data center operators would like to not discuss any data center details, there is a social and environmental impact the public has the right to review.

The Washington State Department of Ecology has approved Microsoft’s additional permit, but has also scheduled a public hearing in Quincy on Sept. 28 to hear from residents on the topic. The Ecology department conducted an evaluation of the health risks from diesel engine exhaust particulates, and found that the Microsoft expansion, viewed in isolation, is not likely to impact public health.

State officials and Microsoft are required to appear at a public meeting to present and discuss the generator expansion. The Department of Ecology took the opportunity to seek feedback from area residents, citing the growing concentration of data centers.

“Due to the interest expressed by other data companies to expand or build in the Quincy area, Ecology was concerned that the cumulative effect of diesel engine emissions should be assessed,” the state said in announcing the meeting.

Being green means more than your PUE and energy efficiency of equipment.

Here is the presentation referenced. Gary Palcisko is the presenter.

And note this slide for potential future requirements.