Cases of carbon monoxide exposure in Maryland up by 50% so far in 2026

Cases of carbon monoxide (CO) exposure in Maryland increased by nearly 50% in 2026 compared to last year, according to data from the State Department of Health.

In 2025, the state recorded a total of 167 emergency room and urgent care visits due to CO exposure. So far this year, 251 cases have been reported, data shows. 

"The times when we get particularly worried about carbon monoxide are; its very, very cold, or the power's gone out, or a combination of both of those," said Dr. Clifford Mitchell with the Maryland Department of Health. "That's when people will frequently try to use heat and sometimes close the windows to keep the cold out, and that's a prescription for carbon monoxide exposure."

More than 400 people die from unintentional carbon monoxide poisoning each year in the U.S., according to the Centers for Disease Control and Prevention (CDC). 

Carbon monoxide exposures increase 

According to the health department's latest report, which details weekly cold-related deaths and illnesses during the winter season, carbon monoxide gas can be produced by alternative heating sources like portable generators or burning furnaces. 

"Anything with a burning flame. Anything that is a source of combustion can produce carbon monoxide," Dr. Mitchell said. 

CO is an odorless and colorless gas. It can lead to illness or death when inhaled. 

"It doesn't take a lot of carbon monoxide to make you sick or kill you," said Dr. Mitchell.   

Symptoms of CO exposure can include shortness of breath, headache, confusion, nausea, dizziness and loss of consciousness. 

"When people get a low dose exposure, the first thing they experience is a headache," Mitchell said. "Oftentimes they don't feel anything until it's too late."

Data from the health department shows that cases of carbon monoxide exposure surged on Feb. 24, with a total of 15 people visiting urgent care or emergency rooms. 12 of those people were from out-of-state, the report shows. 

"We've had a couple of cases where we've had several people transported from the same location," Dr. Mitchell said. "Because fortunately, it's still relatively rare; when we see a large number of people transported, that will make the numbers go up."

Carbon monoxide exposure led to several deaths in the state last year. 

In March 2025, the owner of a Baltimore restaurant died from carbon monoxide poisoning after he and his wife were found in their home with high levels of CO. Costas Triantafilos died, and his wife was hospitalized. The rise in CO was caused by a car that was left running in the attached garage of their Baltimore County home, fire officials said. 

In August 2025, 13 people were evaluated by first responders after a carbon monoxide alarm went off in an Ocean City hotel. Four people were hospitalized after the incident at the Ashore Hotel, officials said. 

64 cold-related deaths in Maryland 

The weekly report also tracks cold-related deaths, which reached 64 during the last week of February, rising by four from the previous week. 

During the 2025 winter season, a total of 75 cold-related deaths were reported in Maryland, a nearly 7% increase from the 70 deaths recorded in the 2023 winter season, data shows. 

Most of the state's cold-related deaths occurred in Baltimore. The city saw a total of 16 deaths so far this season. Baltimore County recorded eight cold deaths and Anne Arundel County recorded five. 

Most of the cold deaths occurred in individuals 65 and older.