At least one company is no longer interested in bidding on a chance to develop a floating offshore wind project off the Southern Oregon coast, and others may also have backed out.

U.S. Mainstream Renewable Power Inc. has confirmed to OPB that it will no longer participate in Oregon’s floating offshore wind lease sale on October 15. Two other developers told The Oregonian/OregonLive that they are also backing out.

These companies are three of five that are eligible to bid on two areas available for wind energy development off the Oregon Coast. Mainstream Renewable did not answer questions about why it was no longer participating in the auction.

These businesses’ withdrawals come as Southern Oregon community groups have raised mounting opposition to the development of floating offshore wind. At least two counties, Coos and Curry counties, will be voting on whether or not to publicly oppose offshore wind, and a tribal group is suing over the federal government’s efforts.

The U.S. Department of Interior’s Bureau of Ocean Energy Management, or BOEM, declined to confirm how many of the five bidders it deemed eligible were still participating in the upcoming auction. The agency claimed the number of bidders was “confidential” before going into the auction. BOEM also declined to comment on whether the agency would delay the auction if only one bidder remains.

According to BOEM, the five companies are “legally, technically, and financially qualified to bid.”

OPB has reached out to all five eligible bidders to confirm their participation. So far, only US Mainstream Renewable Power has replied.

Earlier this month, the Confederated Tribes of the Coos, Lower Umpqua and Siuslaw Indians filed a lawsuit claiming BOEM failed to consider the environmental, cultural and economic impacts of the potential of floating offshore wind. The tribe’s intent is to delay BOEM’s upcoming Oct. 15 auction.

“The Tribe has heard that there may only be one qualified bidder left in the BOEM bid process. The Tribe believes it is in everyone’s interest to cancel the bid auction if that is indeed the case,” tribes’ attorney Rick Eichstaedt told OPB in an email.

“The Tribe, elected officials, commercial fishing interests, and others asked BOEM to pause its process to allow for a better understanding of wind energy impacts and to allow the State Wind Energy Roadmap to be completed,” he said. “Canceling the auction now allows that Roadmap process to move forward before an auction occurs in the future – which ensures that everyone, including wind energy proponents, have a better understanding of measures necessary to protect the Ocean environment, Tribal resources, commercial fishing, and coastal community and maximizing the benefits of wind energy to all of Oregon’s citizens.”

OPB has reached out to Gov. Tina Kotek’s office for comment.

This story may be updated.