A 37-year-old man died and a woman was injured in a house fire in Merrill on Saturday morning. Firefighters responded to a house fire in the 1500 block of River Street around 10 a.m. Two people were inside when the fire started. The man was trapped and firefighters were not able to rescue him due to heavy smoke and fire conditions, according to the Merrill Fire Department. The woman received injuries when she managed to escape. She was transported to Good Samaritan Hospital and then transferred by Spirit Medical Transport to UW-Madison Burn Center, according to the fire department. The condition of the woman's injuries is unknown at this time. The family's pet is currently unaccounted for. The cause of the fire is still under investigation. The fire department said it is unknown if the house had working smoke detectors at the time of the fire.