One hundred and two people in Lancaster County, Pennsylvania, overdosed on synthetic marijuana in three days, according to C. Robert May, director of Lancaster Emergency Medical Services. None of the overdoses were fatal.

“Heroin is normally the issue but in the last week there’s been an overdose of synthetic marijuana,” also known as K2, May told CNN. “The assumption is that heroin is not readily available, so people are turning to K2.”

The treatment of the overdose patients took place between the morning of July 7 through the morning of July 10. More overdoses followed — by the following Friday, July 14, a total of 158 overdose patients were involved in emergency response calls.

According to May, some calls involve two to four patients at once, with a few patients repeating in a span of a few hours.

“This past weekend we responded to one patient nine times in 24 hours,” May said.

In the past six months in Lancaster County, heroin overdoses were averaging eight a day, May said. Over the last week, emergency services responded to 25 synthetic marijuana overdoses a day — about one an hour — in public bathrooms, parking lots, residential homes, on the street and in the parks.

“It’s all over the place,” May said.

Synthetic marijuana, also known as fake weed, K2 or spice, is a mixture of herbs, spices or shredded plant material laced with chemicals similar to THC, the psychoactive ingredient in marijuana. Because the drug is a mixture, the effects it can have on a person vary. Lancaster County District Attorney Craig Stedman said it can often lead to violent behavior.

“I have heard numerous stories from doctors, medics and police officers who encountered a very violent and erratic person under the influence of synthetic marijuana,” he said.

May added that the lack of quality control of chemicals in the drug generates “really sick patients” who are often found unconscious and must be sent to intensive care, while others “are combative and put us at risk,” said May.

He also described the financial burden on the Lancaster Emergency Medical Services, a non-profit, as well as the collateral impact.