WASHINGTON — One person was killed and another is being treated after high levels of carbon monoxide were detected in a Montgomery County, Maryland, home.

It happened on the 300 block of Lawrence Drive off Robert Road in Rockville. Just after 9 p.m., Montgomery County firefighters were called for a cardiac arrest. Rockville City police were already on the scene.

When the firefighters entered the two-story house, the carbon monoxide detector attached to their first aid bag alerted them of the presence of the gas.

They took remedial action and moved themselves and the people in the home outside, where they continued to treat the victims.

Other crews arrived and they found high levels and concentrations of carbon monoxide.

First responders were not able to resuscitate one man, who was pronounced dead at the scene. Another man — the one who called the police for the medical emergency — was taken to the hospital with injuries that are not life-threatening. Four police officers were evaluated but showed no signs of carbon monoxide effects.

The gas was likely the result of a generator running inside, a spokesman said.

Below is a map of the area where it happened.

[google_map latitude=”39.086555″ longitude=”-77.136878″ zoom=”13″ height=”300px” location_label=”Carbon Monoxide_Lawrence Road_Rockville”]