LOS ANGELES – Firefighters, paramedics and emergency crews treated at least three people who fell ill after exposure to an unknown substance.

According to the Los Angeles Fire Department, officers from one or more agencies were reportedly participating in a tactical operation by law enforcement when an unidentified substance was spilled on the sidewalk.

At least three people, all adult males, suddenly fell ill. The incident occurred in front of an apartment building in the 300 block of East Second Avenue. downtown LA Around 11:30 a.m. on Thursday.

Two people were hospitalized, while one refused treatment. The remaining patient was evaluated at the scene until transport by ambulance as the LAFD Hazardous Materials Task Force completed its assessment, LAFD said in a statement.

No one else was injured or sickened. The LAFD said there is no increased threat or danger to the community.

It is not clear what substance they were exposed to. The extent of their illness is unknown. Footage from SkyFOX shows emergency crews wearing hazmat suits. The victims’ clothes were also placed in hazmat bags.

Second Street was closed between Central Avenue and San Pedro Street as a precaution.