MANCHESTER, N.H. (AP) — Manchester firefighters say they were overwhelmed with calls for overdoses this weekend, many involving the synthetic marijuana product known as spice.

District Chief Henry Martineau told WMUR-TV that the first calls started coming in around 8 a.m. Saturday, and the number increased to a dozen in just a few hours. He says such calls are spreading the department thin.

Several of the overdoses happened at the New Horizons Shelter. An official there says spice has recently become a problem at the shelter. Chief Strategy Officer Cathy Khun thanked police and emergency responders, and said it will take multiple partners to tackle what she called a public health crisis.