YORK, Pa. --- Fire crews received a call at 3:50 Wednesday morning for a reported medical emergency on the 700 block of Pershing Avenue.
Deputy Fire Chief Chad Deardorff of the York City Fire Department said when they arrived, they found multiple people unconscious.
“We’re very fortunate we did not go there and find five fatalities involved with this incident," said Deardorff.
A total of five people inside a single family home received medical aid and were taken to a hospital.
Three of them were considered in serious condition.
Also, two dogs received oxygen treatment.
Deardorff said due to the number of people unconscious, they determined the incident was "more than" a medical emergency.
When they metered the home for carbon monoxide, they found 2,000 parts per million of carbon monoxide within the home.
For perspective, Deardorff said a level of 32 parts per million is considered the amount that can be fatal over time.
Investigators say there was a carbon monoxide detector inside the home and it activated Tuesday.
“They took the battery out because they thought something was wrong with the detector," said Deardorff.
Deardorff recommends that if a carbon monoxide detector goes off for any reason to call them to come check it out.
“We’ll come out, check it. We’d much rather come out and find nothing, go back to the firehouse…you’re safe, you have piece of mind…than come out and find a situation where it could’ve potentially been a lot worse,” said Deardorff.
Deardorff and Michelle Hiegler, emergency physician with Wellspan York Hospital, say they see a spike in carbon monoxide-related incidents this time of year.
The reason: as temperatures continue to cool down, more gas-powered equipment is used for heat.
In this case, Deardorff said they believe the cause comes from a crack or a block in the flue area of the chimney.
He recommends having a chimney or generator tested before being put to use.
Also, they recommend putting any gas-powered equipment at a safe distance away from a home.
Officials call carbon monoxide the "silent killer" due to its colorless, tasteless and odorless nature.
Hiegler said side effects include headache, nausea and vomiting.
She said it can seem similar to other illnesses but without treatment in a timely manner, it can be deadly.
"If more than one person in the house is sick at the same time, do the same stuff and it gets better when you leave the house, that’s a sign that something is going on in the house,” said Hiegler
The most recent update from fire officials Wednesday afternoon was four of the people involved remain in a hospital at the University of Maryland.
One of the people involved was released as of 1 p.m. Wednesday.
If you live within the city limits of York City, Deardorff said fire officials can install a carbon monoxide detector as long as you purchase it.
