Ten people suffered heroin overdoses in Fitchburg over the weekend, two of which were deadly, and prosecutors are warning of a “dangerous batch” of drugs plaguing the city in Worcester County.

One person overdosed and died on Friday, and another died early Saturday morning, Fitchburg Fire Chief Kevin Roy said. Six of the overdoses occurred in an eight-hour span Saturday, Worcester District Attorney Joseph Early Jr.’s office said in a statement.

After authorities warned the public about the batch Saturday, there was a dramatic drop in the number of overdoses, Roy said.

“People who are addicted to heroin and their families and friends should be aware that heroin on the streets of Fitchburg ... could cause an overdose or death,” the statement from Early’s office and police said.


Roy said he does not know exactly what was in the drugs that caused the overdoses.

“Certainly something was up,” he said. “There is obviously a problem. It seems to be with the drugs they’re using and some problem with that drug.”

He said the city has “never seen anywhere close to that number” of opioid overdoses in a two-day period.

First responders have been using the overdose-reversing drug Narcan, but doses of the treatment do not always work, Roy said.

“It’s not unusual to have to use more than one sometimes ... to revive the person,” he said. “In two of the cases, they were not revived.”

J.D. Capelouto can be reached at jd.capelouto@globe.com. Follow him on Twitter @jdcapelouto.