A construction crew working near the main building hit a power line, causing an explosion that set a transformer on fire, fire officials said.

A fire and explosion were reported at a Denver-area assisted home facility on Wednesday morning. According to a social media post from the Denver Fire Department, crews responded to the fire around 11:30 a.m. local time. About a half hour later, the fire department said an explosion had been reported inside the same facility.

Residents of the retirement community were not allowed back inside the building Wednesday, according to Denver Fire.