A Colorado law firm is pressing claims that the Internal Revenue Service wields too much power over the cannabis industry, urging a federal appeals court to curb the agency’s authority to unilaterally determine that state-legal businesses are breaking federal law.

Thorburn Walker LLC, a firm that has become go-to tax counsel for many Colorado dispensaries, has asked the U.S. Court of Appeals for the Tenth Circuit to reconsider a panel decision in Alpenglow Botanicals v. United States of America. The three-judge panel on July 3 said a taxpayer does not have to be convicted of a drug crime for the IRS to revoke its ability to deduct marijuana business expenses.