With Monday morning skies that might look and smell smoky, the Maryland Department of the Environment issued a Code Orange and Code Yellow air quality alert for Baltimore and its surrounding counties due to “uncontrolled” fires at the Aberdeen Proving Ground in Harford County.

The air quality alerts will last until at least noon, according to the MDE.

Code Yellow means the air quality poses a moderate risk for people sensitive to air pollution, according to MDE. Code Orange means the air quality is unhealthy for sensitive groups such as children and adults with respiratory and heart ailments.

Harford and Cecil counties, as well as the northern portion of Baltimore County, are under Code Orange. Baltimore City, Anne Arundel, Carroll and Frederick counties are under Code Yellow, along with the northwestern portions of Montgomery and Howard counties.

With the help of the National Guard, the Aberdeen Proving Ground Fire and Emergency Services were fighting multiple fires Sunday afternoon, according to a Facebook post from the emergency services.

The Aberdeen Proving Ground Public Affairs Office did not immediately respond to a request for comment.

The wildfire began Thursday, a day before the Maryland Department of Natural Resources implemented a statewide burn ban. The dry and windy weather, coupled with foliage on the ground, make conditions conducive to wildfires.

“The ban is in response to significantly dry conditions over the last months,” department spokesperson A.J. Metcalf said. “And it has led to lots of dry leaves on the ground. If an open air fire goes sideways, there could be a wildfire.”

The fires at the Proving Ground spread to more than 100 acres, the Chestertown Volunteer Fire Company said in a post on Facebook. The post explained that the Proving Ground is a United States Army testing facility used to evaluate weaponry.

“By the very nature of these testing activities, fires are inevitable, especially during drought conditions like we have ongoing now,” the post read. “Because of the very large number of unexploded ‘live’ rounds down range, it’s far too dangerous to put personnel on the ground for fire suppression. APG has a ‘Let it Burn’ policy for range fires, unless the situation gets out of hand.”

The fires created a smoke plume that blew west toward Edgewood, White Marsh and greater Baltimore on Sunday evening, according to MDE. This led to some people seeing and smelling smoke into Monday morning, though it’s expected to disperse later in the day.

This past October was one of the drier on record for the Baltimore area, National Weather Service meteorologist Austin Mansfield said.

There is a slight chance of rain around Baltimore on Wednesday and Thursday, he said, but temperatures will reach near record highs of around 80 degrees on Tuesday and Wednesday.