Edgewater, MD – Three construction workers were treated at Shock Trauma Tuesday morning after being exposed to potentially lethal levels of carbon monoxide at a work site in Edgewater, authorities say.

Just after 10:05 a.m. Anne Arundel County firefighters responded to the 500 block of Bay View Point Drive for a patient who had a seizure. Firefighters found the man sitting outside a house under construction and determined he had been one of several workers using gas-powered equipment inside a poorly ventilated area.

Firefighters using CO monitors found readings of 45 parts per million at the threshold of the house with suspected higher readings inside. The 46-year-old man was taken by paramedics to Shock Trauma in serious condition for treatment at the Center for Hyperbaric Medicine. A second worker, a 56-year-old man, was also taken to the Center for Hyperbaric Medicine with serious injuries.

A third worker, who had accompanied the first worker to the hospital to serve as an interpreter for paramedics, also complained of possible CO-related symptoms upon arrival at Shock Trauma, the fire department said.

Carbon monoxide is often called the invisible killer. It is an odorless, colorless gas created when fuels such as gasoline, wood, coal, natural gas, propane, oil, and methane burn incompletely. In the home, heating and cooking equipment that burn fuel can be sources of carbon monoxide.

CO poisoning can be confused with flu symptoms, food poisoning, and other illnesses. Some symptoms include shortness of breath, nausea, dizziness, light headedness or headaches. High levels of CO can be fatal, causing death within minutes.