
Deadly yet common gas has been causing people to see ‘ghosts’ for 100 years
Many ghost sightings are chalked up to fantastical thinking, sleep paralysis, and delusions of paranormal activity. But scientists landed on another explanation long ago �one thats arguably more worrying than any other.
From pets being spooked by apparent apparitions to poops that vanish without a trace, the word ghost is used to describe many things. Some are funnier than others. The kind of ghost well get on to in this article probably isnt funny at all. This story is quite serious. But what did you expect? Its spooky season!

The truly worrying reason some people see ghosts
In an academic article published in wait for it 1920, ophthalmologist W H Wilmer, of Washington, describes in detail the case of a family who experienced ghostly apparitions for nine years after moving into a new house.
The paper itself is behind an academic paywall, but IFLScience describes how the husband in the family had a penchant for eating fruit alone in the kitchen before bed.
Then, he started to feel like someone was watching him at all times from behind. He started looking for presences, and that was before the kids became embroiled in the affair.
The children became sick and pale, the outlet summarizes, and lost all interest in playing, while the father hallucinated a strange woman dressed in black walking towards him from the dining room.
“I had vague and strange dreams, which appeared to last for hours,” his wife told Dr Wilmer. They had been to the theater. “When the morning came, I felt too tired and ill to get up. G. told me that in the middle of the night, he woke up, feeling as if someone had grabbed him by the throat and was trying to strangle him.”
What was the reason? Two days after they moved into their house, its furnace broke down and started pumping carbon monoxide into the house, leading to headaches, ill health, and, yes, hauntings.
Symptoms of carbon monoxide poisoning include auditory hallucinations and dread
Investigative journalist Carrie Poppy once appeared on the TED Radio Hour to discuss whether or not science can reveal the truth behind ghost stories.
She begins an anecdote by describing a guesthouse she once stayed in, in Sherman Oaks, a suburb of LA. It was tiny and clearly ramshackle, she says.
One day, she went into an occult bookstore where they specialize in supernatural or esoteric literature and found herself overwhelmed by this negative feeling.
She got home and felt it again, thinking a spirit had followed her to her house. It was like being stared at, and then it grew into a physical feeling: pressure on the chest.�
It got worse before it got better
She began to hear things, including a whoosh as if something had passed by me.
Poppy would cry every night and feel physical pain, so she asked around for advice.
There were skeptics, she says. So she asked them for an explanation. One of them said, OK, have you heard of carbon monoxide poisoning? She looked it up, and it turns out that symptoms include a pressure on your chest, auditory hallucinations, and an unexplained feeling of dread.
Poppy hired someone to test the premises for carbon monoxide, and lo and behold, the skeptic was right. The man told her it was a “really good thing that you called us tonight because you could have been dead very soon.”
The American Lung Association confirms this: Signs that you might have CO (carbon monoxide) in your home include symptoms such as headaches, nausea, dizziness, confusion, and sometimes even hallucinations.
So, next time you see a “ghost,” check that there isn’t a gas leak somewhere in your home!