4 people sickened, including 1 in grave condition, after apparent carbon dioxide leak at LAX

LOS ANGELES -- Four people became suddenly ill after a reported carbon dioxide leak at an LAX terminal on Monday morning, authorities said.

A hazardous materials team responded to the baggage area at Terminal 8 around 7 a.m. to investigate the issue, according to the Los Angeles Fire Department. Authorities said three people were in "mild distress" and a fourth person was in grave condition.

According to the LAFD, the source of the leak is believed to be a utility room in the area. The four individuals were all workers, three men and a woman, who were in or near the room at the time. Authorities added a popping sound was heard shortly before the leak.

One of the workers, a man in his 50s, was found without a pulse inside the room. Paramedics performed CPR and he was taken to the hospital in critical condition.

Officials said some 100 people were cleared from Terminal 8 during the investigation and were sent to Terminal 7 for screening.

Terminal 8 is now reopened after LAFD cleared the building as safe.