SEARSPORT — A high-profile plan to build a 23 million gallon liquid propane storage tank at Mack Point in Searsport is dead.

DCP Midstream, an offshoot of oil giant ConocoPhillips, announced Tuesday that it is giving up its efforts to build the $40 miliion facility on the shores of Penobscot Bay, after three years of contentious campaigning for and against the project.

“It’s phenomenally good news,” said Ken Agabian of Searsport, leader of Thanks But No Tank, a Belfast-based group that has staged protests and planned to file suit against the U.S. Army Corps of Engineers to force it to conduct a more comprehensive review of the project.

“It almost seems too good to be true,” he said Tuesday, April 2, the day DCP announced it was withdrawing its application from the Searsport Planning Board.

The board had already voted 5-0 that the DCP application did not meet certain zoning requirements, and DCP spokeswoman Roz Elliot said it appeared inevitable the local board would vote to reject the tank.

“Obviously we’re disappointed,” Elliot said Tuesday. “We were surprised and disappointed. We did have tremendous support in the town.”

She noted that 600 residents signed a petition of support for DCP, and a much smaller number of local people opposed the tank.

Surrounding towns, including the island community of Islesboro, voiced strong opposition to the proposal, citing safety concerns about shipping and the plant itself. A report commissioned by the Islesboro Islands Land Trust by former White House security advisor Richard Clarke concluded the tank was a bad bet for the Midcoast.

Steve Miller, executive director of the land trust said the news from DCP is “phenomenally good news.”

DCP’s Elliot said the board’s votes thwarted growth for the area.

“We really wanted to bring economic development to Maine,” she said. “We don’t foresee any future capital investment in Maine.”