Excerpts from abc7chicago.com:

Two men were injured, one critically, in a fire at an abandoned home on Chicago’s South Side early Monday morning. The fire broke out about 2:35 a.m. in the 4700-block of South Princeton Avenue in the city’s Fuller Park neighborhood.

The two men, ages 45 and 68, were taken to University of Chicago Medical Center in fair and critical condition, both were suffering from smoke inhalation and one was also burned.

When firefighters arrived at the one-and-a-half story building, the flames were intense, but the fire was put out just before 4 a.m.

The cause of the fire was not immediately available.