The Senate Environment and Public Works Committee will hold a hearing on the Renewable Fuel Standard this fall, Bettina Poirier, a Democratic committee aide, told The Hill on Wednesday.

The announcement raises the specter that changes to the nearly decade-old biofuel-blending mandate could be in the offing.

The planned hearing comes as members on the House Energy and Commerce Committee are working on legislation to overhaul the rule.

The mandate, approved by Congress in a 2005 energy law and expanded two years later, requires refiners to blend 36 billion gallons of biofuel with conventional petroleum by 2022.

Some Democrats on the Environment and Public Works panel, such as Sens. Ben Cardin (D-Md.) and Tom Carper (D-Del.), have expressed concern about the rule.