This action revises the ``National Emission Standards for Hazardous Air Pollutants: Petroleum Refineries'' which was issued as a final rule August 18, 1995. This rule is commonly known as the Petroleum Refineries national emission standards for hazardous air pollutants (NESHAP). This action revises the date by which an Implementation Plan for emissions averaging is to be submitted. Today's action also exempts specific streams associated with hydrogen plants from the requirements for process vents.