PORTLAND, Maine (AP) Spending on a fall referendum aimed at stopping a utility corridor in western Maine has topped $60 million, with energy companies pouring money into advertising ahead of the vote.

It’s already a record for spending on a referendum question in Maine, with about a month to go before the vote.

Since late 2019, energy companies have poured more than $60 million into the fight over the 145-mile (233-kilometer) transmission line that aims to serve as a conduit for Canadian hydropower.

The project, which would be fully funded by Massachusetts ratepayers to meet the state’s clean energy goals, calls for construction of a high-voltage power line from Mount Beattie Township on the Canadian border to the regional power grid in Lewiston, Maine.

Supporters say it would benefit all of New England with renewable energy and stabilized rates. Critics say the environmental benefits of the project have been overstated and that it would permanently disfigure the landscape.

A Nov. 2 referendum question lets Maine voters have their say.

The project received all necessary permits and construction is underway. But a court ruling has called into question a lease for a 1-mile section. More litigation is expected if the referendum is approved.

The two partners on the project, Central Maine Power and Hydro Quebec, together provided about $13 million into the campaign in the last three-month period that ended Tuesday.

Mainers for Local Power received $7 million during the period from NextEra Energy Resources LLC, a Florida-based utility that owns the oil-fired Wyman Power Station in Yarmouth.

Other corporate energy opponents that stand to lose a share of the electricity market, Calpine Corp. and Vistra, also donated money in opposition to the project.