It happened on Cary Reserve Drive around 11 a.m. Police found a car with signs all over it warning of a dangerous chemical inside.
A hazardous materials team from Raleigh was called in to help, and the car was carefully opened.
Inside, emergency workers found the body of a 31-year-old Cary man who apparently mixed some household chemicals together in order to take his own life.
The man's body was taken to the North Carolina Office of the Chief Medical Examiner in Chapel Hill for an autopsy.
While this is the first case of its kind in Cary, ABC11 has learned that so-called "detergent suicides" are part of a growing trend internationally. The first started in Japan about two years ago. There have also been recent cases in California and Georgia.
Emergency workers say the big concern in these types of suicides it that anyone who tries to help could be overcome too.
Mathew Westbrooks, who lives in the area where the Cary man died, said he might have helped if he'd seen what was happening.
"I would probably break the windows down as quick as possible before I ever took a chance to read a note," he told ABC11.
That might have been deadly since the notes in the car clearly read - "Do not open!!! poison gas!!! hydrogen sulfide".
Emergency workers who were first on the scene heeded the warnings and did what another sign in the car said to do - they called the Raleigh hazardous materials team.
"This is a real problem, especially for us as responders and also people in proximity that, you know, you might get a Good Samaritan out there that might see something wrong and may go try and help. And it could be their last breath too," offered Capt. Ian Toms with Raleigh Hazmat.
Toms says his crews approached the car wearing chemical suits and respirators.
The ingredients for the toxic cocktail are easy-to-buy household chemicals. In this case, the victim mixed them in a five-gallon bucket that was sitting in the passenger seat next to him.
When the hazmat team opened the car door, they measured the levels of hydrogen sulfide more than three times the lethal limit.
"I hope this is our one and only occurrence, but I'm pretty confident it probably will not be," said Toms.
And there's the concern that next time, the victim might not leave warning posters.