Supporters of what would have been the nations first statewide pause on large-scale data centers are dismayed by Governor Janet Mills’ veto of the measure.

“We’re incredibly disappointed,” said Sarah Woodbury, legislative director at Maine Conservation Voters.

“The data center issue is not going to go away, and by vetoing this bill, it basically leaves Maine open to allowing these facilities to come in here, and impact our economy and our environment,” Woodbury said in an interview.

Maine’s proposed pause on data centers came as the facilities’ meet pushback across the country. The buildings house circuitry, networks and other equipment for digital services. The massive computing requirements of generative artificial intelligence have led to a construction boom in “hyperscale” data centers that can be the size of three football fields and use enormous amounts of electricity and water.

The bill would have banned permitting and construction of data centers that use more than 20 megawatts of power until November 2027.

In the meantime, a state council would examine issues related to data centers and recommend ways to limit potential harms on electric customers, the power grid and environment.

It passed the Maine Legislature with bipartisan support.

But on Friday, Mills vetoed the measure because it would block redevelopment of a former paper mill in Jay.

Developer Tony McDonald, in an interview, said his project does not carry the same concerns as the data centers causing problems in other parts of the U.S.

The 82-megawatt project would use existing connection to Central Maine Power and less water than the paper mill, which closed in 2023. Local officials have supported the project because of the potential tax revenue and permanent jobs the facility could bring to Jay and nearby communities.

“We ended up finding ourselves in a situation where we had to defend ourselves against concerns that had been whipped up into a hysterical manner by people who are concerned about these big data centers. I think part of their fear is fear of AI,” McDonald said.

The facilities have been built elsewhere in inappropriate places and with inadequate oversight, McDonald said. But that is unlikely to happen in Maine, he added.

“Maine is one of the most highly regulated states in the country when it comes to development. You simply just can’t do that kind of stuff in Maine, even if you wanted to,” McDonald said.

Lawmakers will return to Augusta on Wednesday for override votes on Mills’ vetoes this session.

Rep. Melanie Sachs, D-Freeport, the bill’s sponsor, said previous votes on the measure did not reach the two-thirds majority necessary for an override.

Any non-emergency legislation introduced next year to restrict data centers in Maine would not go into effect until November 2027, Sachs added. By vetoing the bill, LD 307, Maine has missed the opportunity to proactively strengthen its regulatory framework on data centers, she added.

“This veto instead puts Maine in the same position as many other states – trying to put regulations in place after the data centers are already built and significant negative impacts on utility rates, communities and natural resources have already happened,” Sachs said.