A chlorine gas leak at a Hyatt hotel in Chicago forced an evacuation early Sunday morning, disrupting the Midwest FurFest convention.

“Intentional” Gas Leak Interrupts FurFest

The chlorine gas leak set off the hotel alarms around 12:40 a.m., and hotel guests, many of whom were attending the Midwest FurFest, were forced to evacuate the hotel. Midwest FurFest is an annual conference to celebrate the fandom of anthropomorphic animals – with art, literature, games and, of course, furry costumes – and the Hyatt was just one hotel hosting the convention.

Authorities reportedly found what appeared to be powdered chlorine in the ninth floor stairwell, and released a statement calling it an “intentional act,” saying, “This incident is being treated as a criminal matter.”

Despite the ongoing investigation, hotel guests were allowed to return to their rooms sometime around 5 a.m. on Sunday, and the Midwest FurFest convention went on as scheduled.