Biohazard bags are specialized, sizes 18*24,24*36&30*36 leakproof, puncture-resistant plastic bags (often red or yellow) marked with the biohazard symbol, used for safely containing infectious or hazardous medical waste like blood, tissues, and sharps, featuring strong materials (HDPE/LDPE) and sometimes sterilization indicators for autoclaving at high temperatures (121°C+) to ensure safe disposal.