Update, March 21 at 10 a.m.: Three people are in the hospital following a fire that took place at 8106 Whites Ford Way in Potomac on Sunday.

Montgomery County Fire and Rescue responded to the fire and found that the inhabitants, an 85-year-old man and an 87-year-old woman, suffered from smoke related injuries, Montgomery County Fire Spokesman Scott Graham said. The 85-year-old male was transported to a local hospital with 10 percent burns on his body and smoke inhalation -- injuries that could be potentially life threatening, Graham added.

The 87-year-old woman had smoke related injuries and was also transported to a local hospital.

While putting out the fire, a firefighter sustained a small burn on his shoulder and was transported to the hospital. The injury is serious but not life-threatening, Graham said.

The fire started because a cigarette was not properly discarded in the den, Graham said. The couple smoked non fire-safe cigarette meaning that it did not extinguish itself when left unattended.

Maryland passed a law last year banning non-fire safe cigarettes and their sale in the state to help prevent such fires from happening.

Fire and Rescue do not know the cost of the damage to the house; however, the blaze caused extensive damage to the first and second stories as well as the attic.

Update, March 20 at 3:15 p.m.: Two people were injured in a house fire in Potomac Sunday afternoon, Montgomery County Fire Spokesman Scott Graham said. The condition of the two people is not known. 

The house fire, at 8106 Whites Ford Way, is under control but not out yet, Graham said. The cause of the fire is unknown, and the fire is still under investigation.