On May 7, 149 health and medical associations from 49 states and the District of Columbia sent a letter to the President advocating for the finalization of the Tier 3 rule. The rule, proposed by the Environmental Protection Agency (EPA), would lower the concentration of sulfur in gasoline. The groups said the current level of vehicle emissions has dangerous effects on public health. They said the stricter standards will protect children, the elderly, low-income individuals, and those with chronic diseases like heart and lung diseases.