LEWISTON – A hazardous materials team determined Thursday that the mysterious white power found in an envelope at a TD Banknorth processing center early that morning was not a protein-based poison, such as anthrax.

The powder, which was tested on-scene twice, will be sent to a lab in Augusta for further testing to positively identify it. Safety officials expected to learn the results within 24 to 48 hours.

The envelope contained a blank sheet of white paper and the powdery substance, Lt. Mark Cornelio said. There was no return address on the envelope, he said.

Workers at the Atlantis Way processing center, near the Wal-Mart distribution center at the eastern end of the city, were told to leave the building when the powder was discovered. Hazmat teams were dispatched to the center

One woman who was directly exposed to the substance and another person who was later exposed were examined by emergency medical personnel at the scene, police said.

Before the hazmat team tested the powder, acting police Chief Michael Bussiere said, “We have to look at this as a worst-case scenario” by taking the highest possible precautions to protect workers.

Roughly 60 workers were gathered in the back parking lot after a call to authorities at about 8:10 a.m. Workers were later allowed back inside. They were not permitted in the area of the building where the contaminated letter was discovered for the rest of the morning.

Bussiere declined to say who the envelope was addressed to.

Two hazmat workers, wearing full protective gear, entered the building to test the substance, pulling a wheeled cart with testing gear as they moved inside. Two other hazmat workers partially suited up to assist with the testing just before 11 a.m. and were standing by. A portable decontamination shower had been set up outside but wasn’t used after the contents of the envelope were deemed nonhazardous.

Medical personnel took the vital signs of the hazmat workers just before they went into the building and were expected to repeat that process once they emerged, to determine whether the workers were affected by any exposure to the substance.

The envelope and its contents were placed in a sealed plastic capsule, then sealed within a second cylinder. The items were put in a cardboard box and sent to a lab in Augusta for further testing.

Officials at TD Banknorth said the roughly 100 workers at that building were given the OK to return to work by police and fire officials shortly after noon.

“All employees are safe,” company spokeswoman Jennifer Carlson said. “They resumed their normal operations.”

Workers at that building process bank-related materials, including deposits and cash-management activities, she said.

Bank officials decided to evacuate the building as a precaution after the powder was found and police were called, she said.

Carlson said she wasn’t aware of any other instances of mysterious substances found at that building.