A 6-year-old boy died and two women are in critical condition after an early morning house fire Sunday in Prince George’s County, authorities said.

Firefighters found heavy fire and thick smoke coming from the roof of a single-family home in the 2400 block of Griffin Street in Chillum around 3:45 a.m., said Mark E. Brady, a department spokesman. There were four family members at home: the boy, his mother, grandmother and aunt, Brady said.

One woman, reported to be her 60s, made it out before the first responders arrived. Firefighters searched inside the house and found three others, the boy and two adult women, Brady said.

Investigators reported that they found no working smoke detectors in the house.

The injured women, one in her 30s and the other in her 60s, suffered burns and had passed out from smoke inhalation, Brady said. They were partially revived at the scene before they were taken to the hospital. Brady said they have been receiving treatment in a hyperbaric chamber, where they receive pure oxygen to combat the effects of the smoke in their lungs.

“If these ladies are going to survive, that is the treatment they need,” Brady said.

The boy also was taken to the hospital, but he was pronounced dead about an hour after he arrived. Brady said officials are withholding the boy’s name as they await autopsy results.

Firefighters from the Chillum-Adelphi station knocked down the blaze in about 10 minutes, Brady said. One firefighter was treated at a hospital for minor burns but was expected to be released from a burn unit on Sunday, Brady said.

Investigators are working to determine the cause of the fire, but they do not believe it is suspicious, Brady said.

Brady said firefighters and paramedics returned to the neighborhood on Sunday to check smoke alarms and install them for free in any home that needed one.