Hazmat, a term short for "Hazardous Materials," refers to the policies and procedures put in place to deal with dangerous biological or chemical agents. Mission Oriented Protective Posture (MOPP) outlines five levels of protection from MOPP0 to MOPP4, the highest level requiring that an over-garment, helmet cover, vinyl over-boot, mask, hood, and gloves all be worn. The SGC hazmat gear, often brought on off-world missions, includes a complete over-garment, hood and boots, as well as a portable oxygen supply capable of providing protection for as long as 12 hours at a time.
SG-1 has used hazmat protection in handling a number of emergency situations including the nano-virus on Argos, the biological infection on Hanka (MOPP4), the reported chemical spill on level 23 during the foothold situation, the contamination of the Siberian stargate facility, the death of the Linvris, the security breach by Ma'chello's devices, the narcotic effect of the Light (MOPP2), the contagion carried by Ayiana, the disintegration of Alebran due to Nirrti's genetic experiments, the contaminated atmosphere of P3X-289, the exploration of the chamber on Praclarush Taonas, the spread of the Prior plague on P8X-412 and on Earth, the sleeping sickness on Vagon Brei, and when investigating a world where life had been destroyed by the Dakara weapon. Earlier yellow hazmat suits were later replaced in favor of the red over-garments, however, when entering the highly toxic artificial force field created by the Ori on Kallana, SG-1 used complete extra-vehicular space suits as protection from the extremely hostile environment.
Episode Reference: Brief Candle, Singularity, Legacy, Foothold, Watergate, The Light, Frozen, Metamorphosis, Revisions, Lost City, The Powers That Be, Beachhead, The Fourth Horseman, Morpheus, Counterstrike