“We appreciate that EPA was willing to listen to the valid concerns of our industry on their proposed rule,” said Emily Coyner, NSSGA director of environmental services.

The rule directly affects how states and the EPA manage air data, but members would be indirectly harmed by a poor exceptional events policy if states were to impose harsh air permit conditions that could impact production or require expensive additional controls. This rule is particularly important to Western states where dust storms and forest fires can lead to national ambient air quality standards being exceeded.

The rule still requires more effort from state agencies that necessary but the treatment of windblown dust is more reasonable, according to Coyner. EPA has clarified that windblown dust events are natural events and compliance with existing, approved state control plans and permits are sufficient. These changes clarify the rule from previous versions, where it was not clear if the events could impact member permits through revised state requirements.

NSSGA also urged EPA to work more closely with the states during this process, because states have criticised EPA for lack of consultation in the rulemaking process.