The Environmental Protection Agency published its proposed Tier 3 rule on May 21. The regulations require gasoline refiners to reduce the concentration of sulfur from 30 parts per million to 10 ppm between 2017 and 2025. The rule, which was informally released in March, is expected to cost the industry $3.4 billion in 2030 to comply; health benefits are expected to range between $7.4 billion and $23 billion per year. Two days later, the agency announced that it would extend the comment period from June 13 to July 1.