Route 6 in Newtown is closed between Route 25 and the Bethel Town line because of a gas leak.
The gas leak is coming from an 8-inch line under the road and started around midnight.
The fire department is monitoring Maplewood Senior Living and Liberty, two assisted living facilities connected to the line.
Maplewood Senior Living issued a statement on Tuesday morning saying they were notified about the leak around 3:30 a.m. and Yankee Gas and the Newtown Fire Department responded and shut down gas to the building.
Air quality tests indicated no immediate danger, so evacuations were not necessary, according to officials from the senior living center. Gas was restored a few hours later, but it will be shut down again for several hours.
Residents have eaten and are safe, officials said. The building is warm and the temperature is expected to rise into the 50s today.
When gas is again turned off, the facility will be able to serve hot food.
"Although Yankee Gas and Fire Department representatives have told us an evacuation is highly unlikely, we have secured hotel rooms in the event the situation changes," a statement from Maple says. "The safety of our resident and staff is our paramount concern and we will do whatever is necessary to ensure their well being. We have additional staff and senior management on site and will continue to do so until this situation is resolved."
Fire crews believe weather played a factor in causing the leak.
Drivers who must travel in the area should use Interstate 84 exit 9 as an alternative.