The carcasses were discovered near Mills Lake, northwest of Fort Providence and about 100 miles north of the Alberta border, the Canadian Broadcasting Corp. reported.
"A field test on a couple of carcasses did turn out positive," said Judy McLinton, spokeswoman for the Department of the Environment and Natural Resources. "Given the number of carcasses and the chance when they looked at them that it was probably or potentially anthrax, we activated our emergency response plan."
McLinton said wet weather followed by a hot dry spell has made an anthrax outbreak likely. Bison wallowing in mud pick up anthrax spores from the soil and then inhale them, becoming sick.
Because burning all the carcasses will take as long as six weeks, McLinton said they will be treated with formaldehyde and covered with canvas while they await incineration.
Anthrax is a deadly bacterial infection that can also infect humans. People with cabins in the area around Mills Lake have been warned to stay away from bison carcasses and to report any dead animals.