Sue Wallis, who made headlines as a vocal proponent of U.S. horse processing, has died in her home state of Wyoming. A former member of the Wyoming House of Representatives, Wallis was also a principal in a pair of proposed Missouri horse processing plants that never opened.

A representative for Campbell County, Wyo., Cornor Tom Eekoff said Wallis died Jan. 28. She was 56 years old.

Wallis became an outspoken figure in the horse processing debate after Congress voted to reinstate funding for USDA inspections at U.S. horse processing plants. In 2010, as a member of the Wyoming House of Representatives, Wallis successfully proposed HB 122, a bill that allowed Wyoming’s livestock authorities to process abandoned horses and sell their meat. Also in 2010, Wallis was a subject of a complaint alleging that she improperly used her position in the Wyoming State House in order to promote the horse processing project. At the time, Wallis said the allegations were baseless.

In 2012, as Chief Executive Officer of Unified Equine LLC, Wallis announced the firm would establish a horse processing plant near Mountain Gove, Mo. When town residents rejected the plant, Unified Equine announced it would locate a plant in Rockville, Mo. That plant also failed to open