The silent killer claimed two lives in Jacobus this week.
Nancy Rosenbaum-Hardy, 44, and her 15-year-old son Preston were found dead Wednesday in their beds, an indication neither was aware of the danger just down the stairs of their Water Street home.
Carbon monoxide is called the silent, or invisible, killer because the gas is colorless and odorless and victims don't know they're being poisoned.
At low levels, exposure can cause symptoms similar to common illnesses like the flu; at high levels the gas can kill within minutes.
Sources of carbon monoxide are in and around many homes – such as gas-burning appliances, a fireplace or an attached garage. The results can be tragic if an appliance malfunctions, a chimney becomes blocked or a portable generator is placed to close to a house.
In Rosenbaum-Hardy's case, it was a vehicle left running in her closed garage.
Who knows how long it was spewing the poison, which studies show can easily pass through drywall, when the mother and son went to bed Tuesday night?
A family friend who found their bodies at 6:50 a.m. Wednesday immediately was overcome herself by the carbon monoxide and was taken to York Hospital for treatment. Firefighters had to ventilate the single-family home before investigators could enter.
York County Coroner Pam Gay ruled both deaths accidental, the result of carbon monoxide toxicity.
Police say the home was not equipped with a carbon monoxide detector. These are similar in size and cost to a smoke detector – and just as vital, according to the National Fire Protection Association, which recommends every home have one installed outside each sleeping area.
Officials caution the devices are no substitute for regularly inspected, properly maintained appliances and taking safety precautions. But the detectors will warn if the appliances malfunction or if someone is careless or forgetful.
Carbon monoxide is the leading cause of accidental poisoning deaths in the United States, and Pennsylvania had the most at the time of a Centers for Disease Control and Prevention report a few years ago.
Pennsylvania's building code requires new homes to have carbon monoxide detectors, but the number of accidental deaths prompted state Sen. Pat Browne, R-Lehigh County, to write a bill further beefing up safety measures.
It mandated existing multi-family dwellings with a fossil fuel-burning heater or appliance, fireplace or attached garage have the devices installed and required rental property owners to ensure they are properly placed and in good working order. It also required sellers of existing homes to disclose if the properties are equipped with carbon monoxide detectors.
Senate Bill 607 was signed into law late last year and takes effect next June.
The new law, however, cannot force the owners of older houses to install the detectors.
We can only hope the tragedy in Jacobus prompts everyone to check their homes and install the inexpensive life-saving devices if they don't already have them.
They might provide the only warning to the presence of a silent killer.