The Montana Public Service Commission is scheduled to take up the $15.4 billion merger proposal by NorthWestern Energy and Black Hills Corp. on Tuesday.

PSC legal and regulatory staff recommend approval of the merger.

NorthWestern Energy, the largest public utility in Montana, has argued the merger will not harm Montana customers, and some of the parties in the case are in support of the deal following their own settlement agreements with the utilities.

PSC staff recommend approval based on those agreements, including one with the Montana Consumer Counsel, which advocates on behalf of customers.

Released on Friday, a PSC staff memo said the merger will not harm customers.

“The concerns of all intervenors — with the exception of 350 Montana and Montana Farmers Union — were addressed” in the settlements, the staff memo said.

For example, the Laborers International Union of North America Local 1686 requests approval of the merger given the utilities agreed to take steps to support union workers.

Those steps include a “new commitment” giving preference to contractors hiring workers in or near their own communities, Local 1686 said in a filing.

But 350 Montana and Montana Farmers Union describe the merger as “a shell game” that will place financial risks on Montanans. 350 Montana has a mission to reduce atmospheric carbon dioxide.

The two parties urge the PSC to reject the merger — or set conditions that protect Montanans, especially from the potential costs of data centers.

The PSC is a five-member body, currently all Republican, that regulates monopoly utilities in Montana.

“In the end, this is not about love. This is about money,” wrote lawyer Monica Tranel on behalf of 350 Montana and the farmers union. “Enforceable conditions are the necessary prenuptial here.”

The Public Service Commission is scheduled to consider the merger at its 1:30 p.m. meeting Tuesday, Oct. 27. The meetings are available by video on the PSC website.

Nov. 12 is the deadline for a final decision.

Montana is the last state that needs to approve the merger, according to the South Dakota Searchlight. Regulators in South Dakota, where Black Hills is based, approved the deal in June.

The new company, to be named Bright Horizon Energy, would operate in Montana, South Dakota, Arkansas, Colorado, Iowa, Kansas, Nebraska and Wyoming.

This story will be updated.