Multiple people in downtown San Diego fell ill Sunday after ingesting what police suspect to be a “bad batch” of synthetic marijuana Spice. At least seven of the affected individuals were admitted to the hospital, with two of them in critical condition.

According to San Diego Fire Rescue Capt Joe Amador, the rescue calls were primarily for young people, including a thirteen-year-old patient. The Times of San Diego reported that the officers received and responded to medical aid calls from three different locations across downtown.

The paramedics and lifeguards started to rescue people at around 1 p.m. on Sunday. The victims showed mild to serious signs of drug overdose, such as bloody noses to seizures. A few media reports say that some people became ill and passed out in the middle of the street. It is still not clear whether the patients were given the drugs or took them by themselves.

Among the first were victims from 6th Avenue and C Street. Four of them were shifted to a local area hospital, with two of them in critical condition.

San Diego police investigation revealed that the drug was being sold in a black package with a blue dragon printed on the side. The San Diego Union-Tribune reported that police are currently tracking down witnesses and victims. In addition, police have asked the public to be aware of the incident.

Spice is believed to mimic the effect produced by marijuana. It is marketed online and in marijuana stores under the names Annihilation, Black Mamba and Mojo.