Thursday’s events at the Ark Group warehouse on Obici Industrial Boulevard are a timely reminder for all of us about the dangers of carbon monoxide.

About 13 employees there had to go to the hospital after learning the building they had been working in all day had high levels of carbon monoxide — a colorless, odorless gas that is toxic to humans and animals.

It started when someone became unconscious, and emergency medical workers were summoned. After assessing the patient, the quick-acting emergency workers apparently suspected carbon monoxide poisoning and performed a test.

Their hunch was right, and the building had to be evacuated. Employees had been operating forklifts with the doors closed due to the cold temperatures.

Fortunately, according to the city, all of the employees were expected to survive after treatment. Here’s hoping they suffered no permanent damage.

Because heating equipment of various types is a main source of carbon monoxide, the onset of cold temperatures is a good time to remind everyone about the dangers of this silent killer.

At lower levels of exposure, carbon monoxide causes headaches, dizziness, disorientation, nausea and fatigue. At higher concentrations, it can cause chest pains, impaired vision, reduced brain function and death, according to the Environmental Protection Agency.

Sources of carbon monoxide include unvented kerosene and gas space heaters, leaking chimneys and furnaces, back-drafting from furnaces, gas water heaters, wood stoves and fireplaces, gas stoves, generators and other gasoline-powered equipment, and automobile exhaust.

Moderately-priced carbon monoxide detectors are available in most home goods stores. The EPA also recommends these steps to prevent carbon monoxide from building up in your home:

• Keep gas appliances properly adjusted.
• Consider purchasing a vented space heater when replacing an unvented one.
• Use proper fuel in kerosene space heaters.
• Install and use an exhaust fan vented to outdoors over gas stoves.
• Open flues when fireplaces are in use.
• Choose properly sized wood stoves certified to meet EPA emission standards.
• Have a trained professional inspect, clean and tune up heating system equipment annually, and repair any leaks promptly.
• Never idle the car inside the garage.
• Never use a generator inside homes, garages, crawlspaces, sheds or other areas without full ventilation.