Metra commuters may be breathing in potentially dangerous levels of diesel exhaust.
The issue could affect about a quarter of a million people every weekday. According to a Chicago Tribune investigation, levels of diesel exhaust or soot on train cars are up to 72 times higher than the air outside.
The Environmental Protection Agency said soot is a dangerous pollutant and can cause heart attacks, cancer and brain damage. Much of the soot gets inside the train cars when they sit in the train stations with the engines idling.
Senator Dick Durbin is asking for an investigation and wants federal funding to improve equipment, some of which has been used since the early '70's.
"We want to make sure that we have a thorough, complete investigation to determine the dangers for those on trains and walk through the station," Durbin said.
Metra officials say they are looking for solutions and doing testing of their own.
"We're not questioning their methodology or their results. We just want to verify, want to see the extent on our entire system of exactly what the problem is with the emission. And then we want to look at ways to improve upon it, whether it's alterations that can be made to the equipment, whether it's working with the building owner," said Judy Pardonnet, Metra spokesperson.
Most of the toxins are trapped in train cars when the trains are sitting idle in stations by platforms downtown. The diesel exhaust gets sucked in like a vacuum from the engines into the cars.
Many riders Tuesday were concerned about the potentially hazardous air, but others say the issue is being blown out of proportion.
"Where I'm at is wide open, so there's a lot of air coming in. I never really gave that much thought to that. I know it's kinda bad around the engine areas, but once you get past the engine, it's OK," said rider Joe Smith.
"It does concern me, breathing it in day in and day out. A lot of people come through the Metra station," said rider Renee Pitts.
Metra says technically it already fulfills all federal health requirements and filters are on board trains.
Metra officials say Tuesday's meeting is just the first official meeting about this issue, and results will likely come further in the future.