PORTLAND, Maine (AP) — Central Maine Power and Hydro Quebec have spent more money in support of a $1 billion hydropower transmission project than the spending total on a failed referendum on a casino in York County in 2017, an environmental advocacy group said Tuesday.

CMP and Hydro Quebec have together spent nearly $17 million — $10.5 from CMP and $6.2 million by Hydro Quebec, according to records filed with the state ethics commission. That’s more than the roughly $9 million spent in 2017 on the failed casino proposal.

Pete Didisheim of the Natural Resources Council of Maine Advocacy said Tuesday that the level of spending is “obscene.”

Much of the money was spent on legal challenges that are continuing. Supporters of the project sued over the legality of petitions that put the referendum on the November ballot, and now they’re suing over the constitutionality of the referendum itself.

The Maine Supreme Judicial Court scheduled a hearing for Aug. 5 on the project supporters’ contention that referendums must be tied to legislative acts and thus cannot nullify state agency actions.

The New England Clean Energy Connect already received approval from the Maine Department of Environmental Protection, Maine Land Use Planning Commission and Maine Public Utilities Commission. It’s awaiting approval from the U.S. Army Corps of Engineers.

The project calls for the construction of a 145-mile (233-kilometer) high-voltage power line from Mount Beattie Township on the Canadian border to the regional power grid in Lewiston, Maine. Most of the project would follow existing utility corridors, but a new path would have to be cut through 53 miles (85 kilometers) of wilderness.

Supporters say the project would reduce carbon pollution and stabilize utility rates. Hydro Quebec would be the energy supplier.

Critics say the project would spoil part of Maine’s North Woods and that the environmental benefits are overstated.