Washington, D.C. / Baltimore, MD – Winter officially begins today as the DMV marks the Winter Solstice, the shortest day and longest night of the year. While the solstice represents a seasonal turning point and the slow return of daylight, safety officials across Maryland and Washington, D.C. say it also marks one of the most dangerous times of year inside homes, when carbon monoxide risks quietly increase.
The longest night of the year often coincides with colder temperatures and extended hours of darkness, conditions that push heating systems into heavy use. Furnaces, boilers, fireplaces, space heaters, and backup generators are relied on more frequently as residents try to stay warm. With windows closed and homes sealed tightly against the cold, ventilation is reduced, creating conditions where carbon monoxide can build up indoors.
Carbon monoxide is a colorless, odorless gas produced when fuel-burning appliances do not burn completely or are not properly vented. Because it cannot be seen or smelled, it is widely known as the “invisible killer.” According to the Centers for Disease Control and Prevention, carbon monoxide poisoning sends tens of thousands of Americans to emergency rooms each year, with winter months accounting for the highest number of cases.
Medical experts warn that carbon monoxide poisoning disables far more people than it kills, often leaving survivors with long-term neurological or cognitive damage. Early symptoms may include headaches, dizziness, nausea, fatigue, and confusion. As exposure continues, symptoms can worsen to chest pain, vomiting, impaired coordination, loss of consciousness, and death. Because these symptoms often resemble flu-like illness, many people do not realize they are being poisoned until exposure becomes severe.
Fire departments across the DMV consistently caution that long overnight periods—such as those experienced during the Winter Solstice—are especially dangerous. Extended darkness means heating systems may run for hours without interruption, generators may be used during winter storms or power outages, and vehicles are sometimes left running in garages to warm up. Running a vehicle in an attached or enclosed garage, even briefly, remains one of the leading causes of fatal carbon monoxide exposure.
Safety officials urge residents in Maryland and Washington, D.C. to ensure carbon monoxide detectors are installed on every level of the home and outside sleeping areas. Alarms should be tested regularly, and batteries replaced as needed. Residents are also advised never to use grills, camp stoves, or fuel-powered heaters indoors, to keep exhaust vents and chimneys clear of snow and ice, and to schedule annual inspections of heating systems.
If a carbon monoxide alarm sounds, experts say residents should leave the home immediately and call 911 or the local fire department from outside. Anyone experiencing symptoms of carbon monoxide exposure should seek emergency medical care without delay.
As the DMV experiences the longest night of the year, safety officials say the Winter Solstice is more than a seasonal milestone. It is also a reminder that carbon monoxide—the invisible killer—poses a serious but preventable danger when awareness and preparation fall short.
