Per sulfur grade

As of 2025, virtually all gasoline supplied in the U.S. continues to meet the 10 mg/kg average sulfur limit, in line with the Tier 3 vehicle and fuel regulations introduced by the Environmental Protection Agency (EPA). These standards, effective since January 1, 2017, require refiners to ensure that the annual average sulfur content of finished gasoline or blendstock for oxygenate blending (BOBs) at the refinery gate does not exceed 10 mg/kg.

While the 10 mg/kg limit applies as an average across the year, individual batches may still contain up to 80 mg/kg at the refinery gate. The program also includes a credit averaging, banking, and trading (ABT) system. This credit system enables refiners that produce gasoline with sulfur levels below the 10 mg/kg threshold to generate