Ah, crap.
In the HAZMAT world, commercial divers use this phrase quite literally.
HAZMAT stands for “Hazardous Materials, and it comes in all forms of potentially harmful substances for commercial divers.
Some are corrosive chemicals like virgin sulfuric acid, others are radioactive like the water contained in large nuclear reactor turbines. Still others contain lethal bacteria in sewage tunnels under the streets of cities.
Jeff Stiefel, Divers Institute of Technology (DIT) HAZMAT Instructor, defines it best:

Jeff teaching HAZMAT
“Basically any place where there is oil or contaminates; anything other than “clean” water could be considered HAZMAT.”
Sewer Diving Video from National Geographic:
All require special precautions and safety measures from HAZMAT teams.
In cases where the hazardous material is liquid and the team needs a hands-on approach from experienced personnel, they’ll call in commercial divers. These divers serve as the ears, eyes and mouths to the top-side support team.
HAZMAT divers encounter a large variety of situations:
- Repairing sewer valves, sealants, tunnels and old shipping channels
- Adding a chemical base to pack down mud and clear out processing plant cooling systems (clarifying)
- Locating and retrieving objects
- Scouring septic tanks
- Inspecting oil and pollution spills
- Fixing intake valves on nuclear power plants
Someone’s got to get dirty, right?
Poop Pond & Decontamination
Jeff remembers one particular HAZMAT experience.
His assigned project centered on a lodged valve in a basin. Unfortunately, the basin was filled with excrement.
“[It] took 20 minutes. The mental concept of what I was diving in was disgusting, so I just focused on the job of freeing up the stuck valve and reaching surface as soon as possible,” he says.
After a successful dislodging, Jeff’s suit and gear underwent a complete scrub down. Once they finished, his company sent it off for a more thorough decontamination.
All part of the process.
HAZMAT Know-How: DIT’s Program
DIT also provides their own training program for HAZWOPER. It consists of two different courses:
The first course takes the student through in-classroom hazardous material study and chemical reactions. They must study and retain the information in the National Institute for Occupational Safety and Health guide, a standard in the industry. Students will also practice decontamination procedures and proper equipping for the HAZMAT environment.


DIT Students wearing and practicing with Level A HAZMAT suits in the classroom. They are preparing for a walk around campus in these “blueberries.”
In the second course, they’ll put on their diving dress and make use of a couple different diving hats: The U.S.N MK 12 (over 40 years old and still used) and the Desco Pot, both are free-flow style hats. They’ll also work in a simulated HAZMAT environment controlled by the instructors.

DIT Students Simulating HAZMAT environment.
Training doesn’t end with diving school, though.
From Training to Career
Out in the field, each job entails different hazardous materials, challenges and requirements. HAZMAT divers analyze the project with their team, study proper safety procedures and earn proper certification from their employer for the project.
“A JSA (Job Safety Analysis) is done prior to the dive, so that everyone knows the potential hazards of the job and how to overcome them,” Jeff says. “There’s constant communication with the diver and the topside support crew, and the dive can/will be ‘All-Stopped’ until the best method for moving forward with/or aborting the dive is developed.”
Because HAZMAT may involve an array of chemicals, biodegradable material and the occasional sharp object, divers must wear many different hats (professions) during training and on the job.
They must also rely heavily on their team for specialized information outside of their knowledge.
Armed for Hazardous Warfare
What about equipment?
All HAZMAT divers wear special drysuits. Unlike wet suits, these drysuits have extra layers of protection against their environment, armored with a vulcanized rubber that packs more wear and tear than neoprene.

Dry suits are sealed at every joint on the divers’ body, and it uses a special zipper that goes over the chest or around the top of the back. They also have special intake valves that pull in air or take it out. This can control buoyancy and adds air insulation.
HAZMAT divers use free-flow type helmets which creates positive pressure within the hat and prevents contaminants from entering the helmet. It provides a simple but reliable setup, preparing commercial divers for battle in a sea of hostile chemicals and materials.
Broaden the Focus
Often, HAZMAT projects will give a bump in diver pay, since they undergo extra risk. But Jeff makes it clear that you shouldn’t dump all your skills into one pool.
“Yes, there are companies that specialize in HAZMAT, but divers will still need to be a jack of all trades. Just because you go into poop doesn’t mean you aren’t going to turn wrenches.”
Written for DIT by Matt Smith, Creator of Water Welders.