FERNLEY, Nev. According to the National Highway Traffic Safety Administration, more than 100 people die each year in their cars from carbon monoxide poisoning.
The two latest victims: 16-year-olds Alondra Rivera and Zack Dwyer. The two teenagers were found unresponsive in a late-nineties 4-Runner outside Alondra's house late Tuesday night.
Investigators believe carbon monoxide may be to blame. They say there was significant damage to the exhaust system on the Toyota.
Jim Christian, service manager at Wayne's Automotive Center in Sparks says carbon monoxide leaks are common in older cars.
"As they get older, things will wear," he said. "If you have a leak in the exhaust system and you hear that 'pst pst pst' sound you have a leak."
The colorless, odorless gas can easily seep into a car through the floor boards and vents. Depending on the size of the leak, it doesn't take long for the symptoms of carbon monoxide poisoning to set in.
"Headaches, dizziness, not feeling well, those are all signs to look for," Lt. Johnny Smith with the Lyon County Sheriff's Office in Fernley said.
Christian says if you take your car in regularly for maintenance, your technician should be looking for any signs of wear and tear. But he says many times they will catch the damage, but people don't want to spend the money for repairs.
"With the new exhaust system and the catalytic converter, it gets so much more expensive," Christian said. "It use to be around $100, now they're $250 and up."
Officials believe the damage to Zack's 4-Runner occurred when the teens were off-roading, not from lack of maintenance. They say the smell of exhaust was so strong in the car, that the symptoms of CO poisoning may have set in before the two realized what was happening.
But damage or leaks in the exhaust system are not the only causes of automotive CO poisoning. Back in February of 2013, at least two people died in Boston while sitting in running cars during a large snow storm. Officials say the exhaust pipes on both cars were blocked by snow drifts, forcing the CO into the car.
Carbon monoxide was also blamed for the death of "Buckwild" star Shain Gandee back in April of 2013. They say his 1984 Ford Bronco had been stuck in a mud hole with the exhaust pipe submerged.
When people inhale too much CO, it prevents the body from using oxygen carried by red blood cells. Between 1999 and 2004, CO poisoning was listed as the contributing cause of death on 16,447 death certificates in the U.S. according to the Centers for Disease Control and Prevention. About 16 percent of those were classified as unintentional and non-fire related deaths.
Any size leak can be dangerous, especially for people like truck drivers, who spend a lot of time driving and sleeping in their cars. Lt. Johnny Smith says if you feel any of the symptoms, including nausea, vomiting, and confusion, roll down the windows and get out of the car as soon as possible. He also recommends people who pull over to sleep on long road trips, crack the windows to let fresh air into the car in case of a leak.
Christian says the technology exists for manufacturers to place carbon monoxide sensors in cars. But it's unlikely to happen anytime soon.
"They would be placing the sensors in new cars, and most often the damage happens well after the warranty has expired," he said. "That's more money they have to spend now to place them in the cars, which means prices will go up. So until they're forced by [the National Highway Traffic Safety Administration], it probably won't happen.
Carbon monoxide detectors for cars exist, but several local auto part shops do not carry them; you have to order the detectors online.