BANGOR (AP) – A Millinocket mill that was blamed for an unusually large algae bloom in the Penobscot River last month has stopped using the chemical that caused the bloom, mill officials said.

Katahdin Paper Co. stopped using phosphoric acid at the start of the month after identifying a suitable alternative to whiten the mill’s paper products, said spokesman Glenn Saucier.

The company has no plans to go back to using phosphoric acid, which was the primary cause for the 75-mile blue-green algae bloom that prompted the Penobscot Nation to advise tribal members to stay out the river until further notice.

“We put it in a tanker and moved it offsite,” Saucier said.

“That is our commitment. We don’t plan on using it, and if it’s offsite we can’t use it.”

After the bloom was discovered last month, samples were sent for testing to determine if they were toxic. Although no toxic strains were found in the samples, the incident heightened tensions among Katahdin Paper, the state and the Penobscot Nation.

Department of Environmental Protection officials criticized the mill for not notifying the agency that phosphorus was being discharged into the river. After a 2004 algae bloom, Katahdin Paper had agreed to limit phosphorus discharges, but discharge levels were never written into its permit.

Katahdin Paper’s decision to do away with phosphoric acid was welcomed by representatives of the Penobscot Nation and the DEP.

“I certainly hope they do take any measure necessary to prevent the algae bloom from occurring next summer,” said John Banks, director of the Penobscot Nation’s Department of Natural Resources. “If that’s what it takes, then they’re on the right track.”

The new whitening product costs up to two times as much as phosphoric acid, Saucier said. So far it seems to be just as effective, he said.

“It’s the right move, but it took us a little bit of time to figure everything out,” Saucier said.