One person died and four people were hospitalized after residents of a Denver home reported an unexplained odor and difficulty breathing early Tuesday morning, according to the Denver Fire Department.

Firefighters responded to a single-family home at the intersection of East 41st Place and Esenada Avenue in Denver’s Green Valley Ranch neighborhood at 7:26 a.m. Tuesday after residents called 911 and reported difficulty breathing, Denver Fire Department spokesman J.D. Chism said. He said he did.

One adult died. He said two children and two adults were taken to hospital for treatment. Two more people were evaluated at the scene, Chism said.

The identity of the deceased has not been publicly disclosed.