A fog machine malfunction at a Teen Choice Awards pre-party has sent six people to the hospital and forced the evacuation of a Hollywood nightclub.

Los Angeles Fire department spokesman Brian Humphrey said about 400 people were attending a concert for the boy band Midnight Red when the machine released a large amount of carbon dioxide Saturday.

Humphrey says that within seconds, there was zero visibility inside the Avalon nightclub. He says the accident prompted the club's staff to evacuate the venue.

He says six people, ranging from 8 to 20 years old, were taken to the hospital for problems ranging from headaches, dizziness, shortness of breath, and cryogenic burns.

The band tweeted that the accident caused a "small panic" and blamed fire marshals for canceling the concert.