Protecting Yourself Against the Hazards of POLLUTED WATER DIVING

Protecting Yourself Against the Hazards of POLLUTED WATER DIVING

FEATURES

PROTECTIVE CLOTHING

Since 1974, the U.S. Coast Guard Office of Marine Environment and Systems has recorded over 450 large spills or release incidents in our nation’s waterways, involving more than 209-million pounds of hazardous substances. In addition to these accidents, many bodies of water are subject to continuous dumping of effluents either through design or neglect. And, periodically, emergency service divers are required to enter these environments to rescue or recover a victim(s) from a submerged vehicle.

Obviously, while it will be rare for a diver to come into direct contact with concentrated or pure chemical products, due to the inherent diluting characteristics of water, such a potential still exists. Chemical drums and pipelines may be submerged and in danger of rupturing. High concentrations of hydrogen sulfide accumulate near the point of discharge of municipal and industrial wastes. Ingestion of petroleum products can cause burns, skin cancer, and central nervous system damage.

Just as a firefighter’s turnout gear is his first line of defense against burns and injuries, so too is a diver’s gear his first line of defense against the myriad organisms polluting the waters.

Even in relatively clear water, contamination may be present, and these biological organisms can cause severe gastrointestinal disorders lasting anywhere from two to ten days or longer. A diver with the Houston Police Department was incapacitated for more than a month after diving in a Texas bayou.

Traditionally, most emergency service divers are equipped with neoprene wet suits. The thermal protection theory of the wet suit is that a small quantity of water is trapped between the diver’s skin and the suit. The water is warmed (at the diver’s expense) to the diver’s skin temperature. Obviously, the wet suit affords little thermal protection, and absolutely no protection from chemical or biological hazards.

A helmet/suit combination such as the one used by the U.S. Coast Guard's National Strike Force Dive Team is a must to protect emergency personnel operating in polluted waters.

Photo by Steve Barsky

Dry suits are the logical alternative to wet suits, but not all dry suits afford acceptable protection in a contaminated environment. To be effective, a dry suit must seal at the wrists, neck, and feet. Better dry suits come equipped with attached hard sole boots which are a must for contaminated water operations.

Dry gloves that fasten directly to the suit by means of an inner and outer rubber snap ring is another important feature of the dry suit system, as any exposed skin is subject to chemical bums, while open cuts are invitations to infection.

The suit is opened and closed by a waterproof/pressure proof zipper in the shoulder area. These zippers are especially rugged and are the same type used in space suits.

Although dry suits come in a variety of materials, only vulcanized rubber is acceptable for polluted water. Studies by Otis P. Daily and James C. Coolbaugh of the Naval Medical Research Institute in Bethesda, MD, have shown high levels of bacterial contamination on nylon coated dry suits even after the suit had been disinfected and unused for several days. Dry suits made of vulcanized rubber (EPDM), on the other hand, were shown to be easily disinfected and to retain a minimal number of organisms between dives.

Dry suits should also be equipped with automatic buoyancy control valves and heavy-duty wrist seals so that divers can have their hands free to work. An automatic buoyancy control valve also helps prevent suit over-inflation.

Full coverage of the head is an absolute must when operating in polluted waters. Conventional self-contained underwater breathing apparatus (SCUBA) is totally inadequate for this application. Regulator mouthpieces have water seepage at the lips. Full face masks can be dislodged and, even at their best, permit exposure of the head, neck, and ears. Most diving helmets permit a backflow of contaminants through their exhaust mechanisms. Lightweight fiberglass helmets are available which are easy to use and highly reliable. They also provide superior communications and an unlimited air supply.

This type of helmet has a special “double exhaust” system consisting basically of two exhaust valves operating in series. This mechanism prevents a backflow of contaminants into the helmet.

There is also a mating system to join the helmet to the dry suit. This system must provide a 100% watertight seal and prevent any contaminants from being trapped in the helmet/suit interface. The inside collar of the suit is fitted with a ring clamp that fits on the O-ring seal on the outside of the helmet.

Simple topside dive control systems and lightweight diving umbilicals complete the package, allowing for a rapid deployment capability. Unlike the bulky systems of the past, the new generation of surface supplied equipment can be transported in the trunk of a car or operated from an inflatable boat.

Protection for guideline tenders is as important as protection for the divers themselves. While the surface environment may be “clean,” tenders must be able to safely handle wet (i.e., contaminated) equipment. Normal methods of protection (such as hazardous material suits) may suffice, although it may be desirable to equip tenders with self-contained breathing apparatus (SCBA) to avoid inhalation of and facial contact with spray or fumes.

This schematic shows the type of double exhaust system that must be mounted in the diver’s helmet to prevent backflow of contaminants into the diver's breathing system.

Decontamination for biological hazards requires a Betadine or Zepamine scrub followed by a rinse; specific chemical hazards call for individual neutralizing agents.

No matter how reliable a dry suit is, divers should never be allowed to operate in waters containing certain highly toxic chemicals, such as acetic anhydride, bromine, methyl parathion, acrylontrile, epichlorohydrin, and chlordane. Of course, any chemical that will dissolve latex rubber, as used in diving helmets and suits, would, obviously, be off limits.

It is imperative that any department asking a diver to operate in hazardous environments use every available resource to alleviate the potential dangers. Diving in contaminated waters will never be pleasant, but with the proper protection, it can be safe.

The situations encountered will dictate the type of equipment necessary for a diver to operate safely. A full face mask may only be used in situations where contamination is minimal. A dry suit with helmet and surface supplied air is recommended for contaminated or suspected waters.

Photos by Steve Barsky

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