Marius Mason, an Indiana-born environmental and labor activist, pleaded guilty in 2008 to a 1999 arson at a Michigan State University genetic-engineering lab and to related property actions carried out with the ELF — crimes against property that harmed no one, committed years earlier. Turned in by his ex-husband, who cooperated after his own arrest, and refusing to inform on others, Mason was sentenced in 2009 to nearly twenty-two years with a terrorism enhancement — the longest sentence of any Green Scare defendant, and far beyond the guidelines range the parties had contemplated.

In prison Mason came out as a transgender man, becoming the first federal prisoner to win access to gender-affirming care in a men's-designated facility only after years of advocacy, much of it from the Carswell administrative unit in Texas — a high-restriction women's unit with conditions likened to the shuttered Lexington HSU. An international June 11th solidarity day carried his case for over a decade until his release from prison in 2024. Mason's sentence remains the movement's benchmark for the Green Scare's asymmetry: twenty-two years for property, while corporate destruction of ecosystems is regulated, fined, and legal.