- Black Mesa Security Division, BMSD for short, is a private security force employed by BMRF themselfs, not to be confused with DOE Security Force employed by USMC. While such experience would obviously be preferred, BMSD doesnt exclusive hire ex-military or law enforcement, but also those with little to no work experience as long as they can pass rigorous background check and security training. All BMSD personnel are deputized, granting them power to arrest and hold violators if and when necessary, however since they arent technically speaking actual law enforcement they are required to hand over any such violators to DOE Security Force. On-duty members of BMSD are rarely if ever seen outside of the facility.

-BMSD is much less lenient than Research & Development Division when it comes to uniform policy. All guards apart from special sub divisions, namely HEV security and Special Security Force, are required to wear the same dark blue pants, ligh blue shirt with dark blue highlights, with both long and short sleeve versions of this being available depending on personal preference, black boots and black tie with tie clip being issued for all divisions. BMSD are very often seen wearing a vest, either a standard issue Black Mesa branded bulletproof vest or simple dark blue load bearing vest depending on the assignment of an officer. These are not however universally required in all parts of the facility. In some areas with lower security clearance (such as in and around dormitories) its not uncommon to see on-duty guards without vest entirely. Therefore lack of holster is generally a better indication of whether or not guard is on-duty or not. Alongside vests, security jackets are also a fairly common sight. These are supposed to be used by security officers in or near topside areas during night shifts, but its not uncommon to see guard with one during daytime as well either for protection from the wind or simply because the officer likes wearing one. Often security officers in patrol duty or guarding important entrances are also issued with utility belt for holding a flashlight, zipties, pepper spray, extra ammo, set of keys for their assigned areas as well as other miscellaneous equipment. Variant of PCV created for security use exists in form of UPV, however this is only issued to FRTOU as type of heavy vest due it not being cost effective to issue it for every branch let alone every member of BMSD. It is generally suggested by Black Mesa administration that guards wearing helmets should tuck their pant sleeves in to their boots but this is not strictly enforced as part of the BMRF's dress code for security personnel, often leaving it up to individual to decide how they wish wear their pants as long as they wear them. Walkie talkies and headsets are also issued for communication purposes.