The White House is considering waiving U.S. gasoline environmental rules aimed at reducing summertime smog as a way to combat rising pump prices, according to three sources involved in the discussions.

Refiners and blenders are required to avoid lower-cost components like butane in summer gasoline, but the White House is weighing suspending that rule to help lower fuel costs. The components help elevate gasoline's reid vapor pressure, which contributes to smog at higher levels.

No final decision has been made, the sources said.