OK if you want to use phrases, how about "There's no smoke without fire."
People don't worry about things unless there is a reason for it. Things can get blown out of proportion, but fumes incidents are something that have been swept under the carpet for a long time, so have in reality been under investigated as the potential costs if a problem is found are astronomical.
So there has been a culture of not looking as the risks of finding something are too great. (Read too expensive.)