Saving 10 to 15 cents a gallon may sound good, especially at a time when it feels like every penny counts but scientists said there is a downside to butane in summer gas.

Just like it does in a lighter, butane evaporates quickly into the environment, causing ozone pollution on hot summer days.

“And so the fact that it likes to evaporate from the gasoline instead of going through the engine is what makes it a serious thing when it comes to ozone pollution,” said Neil Donahue, an atmospheric chemist at Carnegie Mellon University.

Donahue said butane in summer gas would cause health problems whose cost far outweighs the 15 cents per gallon savings.

“Putting butane in gasoline in the summer to lower the sticker price to make gas cheaper, makes using that gas more expensive. We pay in people getting sick,” Donahue said.