Gas Tanks were initially part of a special cleanup unit that was sent into the city of Harran and were subsequently killed. Many of the Gas tanks roam the city, still in their hazmat suits.
Gas Tanks are just as slow as the Biters, however unlike other infected, Gas Tanks have red oxygen tanks on their back that can be set off when hit. Since the Gas Tanks cannot remove their helmets, their hazmat suits prevent them from biting, but also makes them fireproof, and can still attack with their fists. Their hazmat suits also protect them from dismemberment and decapitation, and make them much more resistant to being knocked down by melee strikes.
Gas Tanks are able to undergo a rapid and sudden transformation during the night similar to Biters, when a Gas Tank turns into his Night Walker variant he will attempt to suicide himself into the player character.
- Gas Tanks have about 350 to 400 health. This makes them noticeably more durable than regular Biters early in the game (who start out with about 150 to 200 health). However unlike Biters, Virals, and Rais' Men, they do not scale in level as the player's Survivor Level increases. At Survivor Level 25, Gas Tanks have roughly the same amount of health as regular Biters.
- To deal with this infected, a good strategy is to strafe to the side before it strikes you and aim for their oxygen tanks. If you rupture the tank, quickly back-step away from the danger until it explodes into a red mist. However, much like normal explosions and other loud noises, it will draw virals to your location.
- If a group of Infected are in your way and a gas tank remains in the horde, use firecrackers to lure the horde and then strike the oxygen tanks, this will cause the oxygen tank to explode and kill most of the horde.
- Detonating the oxygen tanks will cause a loud explosion — attracting nearby virals. It is recommended to knock this unit type down and strike the head repeatedly if you do not wish this to happen. If you have Stomp skill you can kill it quickly once it's been knocked down. Oddly when using the stomp skill, their helmets and their visors remain intact.
- The Tackle, Dropkick, and Brutal Grapple techniques are ALL excellent ways to down a Gas Tank and to finish killing them by using the Stomp technique.
- Because the tanker cannot bite or grab you, its attack range is relatively low and predictable.
- Bullets fired into a Gas Tank's chest will penetrate through the body and can set off their explosive gas tank. This can be exploited to detonate gas tanks from a distance without having to get behind them.
- Due to Gas Tanks technically being Toxic Biters, Gas Tanks will retch while kneeling down before dying.
- Gas Tanks are the only infected who cannot be used with the Camouflage skill and the Takedown skill.
- Be careful when hitting the oxygen tanks on their backs as they can be propelled in your direction. When timed right, the oxygen tank can be used as a weapon to take out nearby infected.
- Once introduced to the Gas Tank, you will notice throughout the game, almost no matter where you go or how empty and secluded the area you stumble upon is, there will almost always be one or two Gas Tanks shambling around, often headed your way.
- After beating the main story, the Gas Tanks may seem to disappear for a while, until the player finds a Quarantine Zone where it would be more likely for them to have been, as HAZMAT crew members. They can then be found normally. (Tested on PS4 Version)
- Oddly, though the Gas Tank cannot bite due to their visor, there is typically a rather large amount of blood flowing from the rim of said visor, as if it was someone else's. This is confirmed in Dr. Camden's lab where you see several of them feeding near a Demolisher.
- Another oddity, is that it was stated by a survivor, who was with the HAZMAT crew, that the others were infected by biters being able to bite through the suits. However, the Gas Tank's suit appears to have no visible holes or other damage.
- No matter what weapon the player uses, the suit of the Gas Tank cannot be damaged. Slashing them will cause them to simply die, or hold their bellies, retch violently and then die but the suit will remain unharmed. Stomping also does no damage, and the suit is fireproof.
- In The Bozak Horde, Be The Zombie, "Extraction", or during a level 4 pursuit, the player can encounter running Gas Tanks. They can be extremely dangerous, as not only the player can hit the oxygen tank on their back and they can still run after you, even with the tank activated, but they can also explode like a bomber. It is cautious not to be near them when exploding and keep avoiding them as much as possible.
- It is unknown how they are able to cause their oxygen tank to explode at the right moment, but the important thing is to not misinterpret them as simply a Hazmat Viral attempting to get close enough to swipe at the player.
- If you hit the tank, the gas will release, quickly enough to boost the Gas Tank into the air. They will fly around until the gas runs out and explodes or if they hit a player, killing them.
- When engaging NPC Survivors, Gas Tanks will attempt to grab and bite them just like a normal Biter, but will be unable to do so. This makes them much less of a threat towards NPCs than regular Biters.
- In the area around the fishing town settlement you can sometimes encounter a surviving gas tank, with his suit off he explains that he was part of a hazmat crew that got killed during a checkup when attacked by a viral.