The Tenth Circuit Court of Appeals has determined that EPA can revise a tentative interpretation governing the handling of magnesium waste without conducting a formal rulemaking. U.S. v. Magnesium Corp. of Am., No. 08-4185 (10th Cir. (8/17/10). The case concerned the regulation of magnesium process wastes and waste byproducts at defendant’s mine and plant in Rowley, Utah.  

EPA had initiated an enforcement action against defendant in 2001, alleging noncompliance with waste management regulations under subtitle C of RCRA. Defendant argued that facility wastes were exempted from subtitle C under an agency interpretation contained in a report to Congress and that, to revise its interpretation, EPA was required to conduct a formal rulemaking under the Administrative Procedure Act. The federal district court in Utah agreed and granted defendant’s motion for partial summary judgment; the government appealed.  

Reversing the district court, the appeals court held that the prior EPA interpretation was repeatedly described as “tentative” in the report, submitted in response to congressional action that required the agency to determine under the Beville Amendment whether it could regulate ore and mineral processing wastes under subtitle C or subtitle D. In the report, EPA noted that its tentative findings were subject to comments from interested parties. According to the court, an EPA decision to revise a tentative interpretation of a regulatory provision does not require formal notice-and-comment rulemaking. The court remanded the case to the district court for further proceedings.