Relating to the use, possession, delivery, or manufacture of testing equipment that identifies the presence of a substance listed in Penalty Group 1-B or xylazine.

HB 1644 exempts individuals from certain drug law penalties when using, possessing, delivering, or manufacturing equipment that tests for fentanyl, its derivatives, or xylazine. It directly affects harm reduction organizations, first responders, and public health workers who use testing kits to identify these substances in communities. The bill adds a new exception (Section 481.125(j)) to Texas' Health and Safety Code, clarifying that testing equipment for these specific drugs is not subject to criminal penalties under existing law. The exemption applies only to equipment testing for fentanyl, alpha-methylfentanyl, or xylazine, and takes effect September 1, 2025.