In mid 2024, community-based drug checking programs discovered the industrial chemical bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (BTMPS) in the illicit opioid supply in Portland, Oregon and Philadelphia, Pennsylvania. The substance appears as a white powder, and on industrial chemical websites, it is often referred to by its brand name, Tinuvin® 770. Used, among other things, as a protective coating on plastics to provide protection against ultraviolet rays, BTMPS belongs to a class of molecules called hindered amine light stabilizers. It is not approved for use in humans or animals, and it is not a scheduled or regulated substance in the U.S. This fact sheet provides an overview of the sudden increase in the presence of BTMPS in the illicit drug supply and its rapid proliferation across the country, which has left drug policy experts and harm reduction specialists puzzled as to why it is in the supply and how it will affect the individuals consuming it....