Luke Seabrook was a 39-year-old commercial diver from Dartmouth, N.S. On July 15, 2015, he was inspecting a gate at a Nova Scotia Power tidal plant in Annapolis Royal. The gate was locked out by the power company and the controls indicated the gate was closed. However, the gate was not completely sealed — it was ajar about 12 to 18 inches. Due to a difference in pressure from the water levels on either side of the gate, a vacuum effect was created. Seabrook was pulled into the gate where he became trapped and drowned.
“He didn’t have a hope in hell; nobody would,” said Angela Seabrook, Luke’s mother, to the CBC.
Seabrook’s employer, Paul’s Diving Service, pleaded guilty and was required to pay a total of $34,000, a mix of fines and a donation to a safety education fund. The company was also required to conduct 15 safety presentations.
Additionally, Seabrook is suing Nova Scotia Power, claiming damages under the provincial Fatal Injuries Act.
Commercial divers work for a variety of different industries, including aquaculture, fish farming, construction, offshore oil and gas, law enforcement and utilities. They may be undertaking inspections, maintenance or construction work. On any given day, a commercial diver can be found breaking up rock with a hydraulic jackhammer, pouring concrete under water and rigging up cars to be hoisted out of a lake.
Regardless of the job, occupational health and safety needs to be the first thing that commercial divers think about before they dive in.
“There is pretty well zero margin for error. It’s not very often that divers are injured. They usually just end up dead,” says Aaron Griffin, program co-ordinator, underwater skills, Seneca College in Toronto.
The phenomenon that took Seabrook’s life is known as Delta P — the number 1 killer of divers. Differential pressure (Delta P) refers to an underwater hazard on or near a water control structure (such as a dam) where a difference in pressure exists because of a hole, gap or crack in the structure, according to the Canadian Association of Diving Contractors (CADC). Delta P also occurs at the intake of suction pipes or at any location where there is an unequal pressure difference.
“If you imagine a drain for a hot tub, you’re sitting in there but you can feel the water pulling into the drain. Now imagine you’re a diver — we can get sucked into those places and either trapped or pulled right through,” says Kelly Korol, director of training and operations at DiveSafe International in Campbell River, B.C . “Delta P is very unforgiving. It’s basically you’re in front of a pipe that’s got flow and you’re sucked right into it, and it’s usually fatal. It’s our biggest worry.”
To prevent Delta P, a simple bag test can be conducted — something Paul’s Diving Service failed to do. A bag is filled with a bit of sand (about 5 pounds worth) and is tied to a rope. The bag is raised and lowered slowly across the entire structure where the diver will be working. A severe draw on the bag and rope or anytime where the bag is trapped and cannot be pulled free are indicators of a serious Delta P hazard, according to the CADC.
“It can have devastating consequences if you don’t do it. I’d much rather have a sandbag stuck on the wall that I never have to worry about than a diver, because you’ll never get a diver off of there,” says Griffin.
After a successful bag test, a recognition dive should be conducted to establish a safety zone. This dive is performed in order to identify any signs of a potential Delta P hazard, such as structural damage, accumulation of debris, cracks, holes and gaps, according to the CADC.
Once the safe zone is established, a restraint should be placed on the diver’s cord (called the umbilical) so they cannot swim outside of this zone during work.
Lockout is another very important component in mitigating this hazard. Valves and machinery must be locked out — but indicators can’t be trusted, says Griffin.
“The normal procedure is yes, the indicator shows it’s down, but you actually physically need to check to make sure that all flow hazards have been stopped — visually confirm,” he says.
Divers are very familiar with decompression illness (DCI), a disease caused by the improper or incomplete elimination of inert gas from body tissues. The gas is absorbed by the body while breathing in a high-pressure environment.
“This forms bubbles much like opening a bottle of soda water too quickly. Bubbles get stuck in blood vessels, joints and possibly the spine and brain, causing tissue damage, pain, nerve and brain damage and possibly death,” says Griffin.
Almost all the provincial occupational health and safety authorities require commercial divers to use decompression tables to prevent DCI. The tables outline how divers should return to the surface so the pressure is not reduced too quickly.
“Your bottom time is limited the deeper you go,” says Griffin. “If you exceed your no decompression limit — your bottom time — you would have to do decompression stops on the way out. Instead of just coming right up to the surface and going about your day, you might have to stop at 20 feet for 10 minutes and then 10 feet for another 10.”
Symptoms of decompression illness include fatigue, skin itch, joint pain, dizziness, vertigo, numbness, tingling and shortness of breath.
“You will rarely ever hear of a diver dying from decompression sickness. If we do, it’s usually a diver who wasn’t following the dive tables,” Korol says. “Some of them are just old-time divers who are uneducated, and they just think that they know better.”
If a diver does have a decompression illness, a physician must be alerted and the worker needs to be taken to the nearest hyperbaric chamber for treatment. The treatment involves breathing pure oxygen at elevated pressures for a specified length of time.
Hyperbaric chambers are required to be on site whenever planned dives exceed the no-decompression limit or a depth of 130 feet is exceeded, according to the CADC in its guideline for the CSA Z275.2-15 Occupational Safety Code for Diving Operations standard.
SurDO2 (surface decompression using oxygen) is a method that dive companies can use to reduce the amount of decompression time in the water. The diver does some short in-water decompression stops and then comes to the surface and fulfills the remainder of his decompression requirements in a hyperbaric chamber, breathing 100 per cent oxygen.
Cold stress is something that divers need to be prepared for if they are working in cold water. They wear heavy dry suits with thick underwear, but if the suit leaks, a diver can get cold pretty quickly. Korol says as soon as divers feel shivering coming on, they need to get out of the water and warm up.
“Unfortunately, because divers tend to be a little bit on the macho side, a lot of them will push through that until it’s too late, until it becomes the point where they are almost incapacitated under water because they don’t want to admit they’re getting cold,” Korol says.
Sometimes divers are put in a big, over-sized wetsuit that has hot water pumped into it.
“It’s great for the diver. It’s like they’re working in a bit of a hot tub. It’s very comfortable — until the hot water machine fails and they get immediately cold and they have to get out of the water immediately,” Korol says.
The top-side crew — individuals who stay above water to assist with the dive — can be very helpful in determining if the diver is experiencing cold stress. As they are in constant communication with the diver (who has a communication device built in to her helmet), they should be listening for chattering teeth or irritation.
“They have to listen. They have to hear things starting to develop with the guy underneath,” says John Pegg, owner/program co-ordinator for Canadian Working Divers Institute in Chapleau, Ont. “If he’s usually pretty even-keeled and he is getting frustrated on the bottom, there’s a level of discomfort there for some reason.”
Before a dive begins, the site needs to be assessed for potential contamination hazards. Whether they are diving in a marina, nuclear power plant or effluent ponds, an industrial hygienist should be called in to take a sample of liquid and identify the various hazards.
“You have to know what you’re diving into and take precautions against that,” says Griffin. “Whether it’s chemical contamination, biological contamination, especially in the old harbours where they dump raw sewage into the water, you don’t want to be diving into that without special procedures and equipment.”
If the water is highly contaminated, the diver would be required to wear a helmet that is mated and sealed directly to a rubber suit, so she is completely encapsulated from the environment. The helmet is flooded with a positive pressure of air, so water can’t leak back in on the diver.
The biggest concern is biological contaminants, which used to be ignored in the olden days of diving, says Korol, explaining that was just about 30 years ago.
“Now we are realizing that in the water, there’s e-coli and listeria and all kinds of nasty little bugs that if we’re diving on scuba, those things get in our ears, our eyes, mouth and nose.”
In addition to having the right equipment, the dive crew should have neutralizing agents for the hazard available. For example, if it’s an acidic environment, they would have a bath of sodium bicarbonate to neutralize the acid, or if it’s biological, they will have a disinfectant that can be used.
When the diver comes out of the contaminated water, the top-side crew will follow procedures to decontaminate him before he can remove the dive suit. Anything that enters the contaminated environment has to be cleaned, washed and inspected, says Pegg.
To get ahead of all these hazards, comprehensive hazard assessments and pre-dive checks are crucial. The location, water depth, water condition and visibility are just some of the factors that need to be assessed before a job begins. The weather conditions can also have a big impact on the dive and the gear required.
“We’ve had situations where a diver was climbing up a wharf out of the water and was frozen to the ladder,” Griffin says. “We had to pour coffee on his hands to be able to get him out. It’s like sticking your tongue on a fence post in the winter.”
Aside from looking for the hazards, Pegg recommends looking at past job history at the site.
“It’s something that’s not very commonly heard but that I believe strongly in: If I have not done it before, I am going to get a hold of people. Communication with other companies or workers who have done this type of work and what they encountered as any problems.”
The remoteness of a job needs to be taken into consideration in case an injury occurs. Griffin was recently doing a job in the arctic and his crew members were the most qualified people in 1,000 miles.
“We had to make sure that we had everything with us because we were totally on our own if anything went weird. That means advanced medical equipment, advanced medical training and that kind of thing because we would be 15 hours from anybody if something went sideways,” he says.
All commercial divers have to be trained to the CSA Z275.4 Competency Standard for Diving Operations and certified through the Diver Certification Board of Canada. Through this education, they are trained on the medical conditions and physiological problems that could occur due to diving, as well as dive accident management. They are also required to hold current first aid, CPR, AED and oxygen provider certificates.
It’s important to have an emergency evacuation plan in place, says Korol. The plan should outline how to get an injured diver out of the water, onto the vessel safely and transported to the hospital. Before the dive, it should be confirmed that breathing gas quantities and back up supplies are adequate and first-aid kits are readily available. All divers must wear a scuba bottle on their back, which acts as their emergency air supply.
“We never say, ‘Well, if we have an accident.’ It’s ‘When we have the diving accident,’ so it puts everybody in the frame of mind that yes it’s going to happen one day and we’re going to have to deal with it. And then you’re prepared better,” he says.
In offshore and very remote areas, more and more employers will have a diver medic technician (DMT) as part of the crew — someone who has even more advanced medical training than a standard diver.
A DMT is crucial for saturation diving, where the diver works at depths of over 500 feet and spends weeks living in a pressurized environment on a ship or a barge.
“If you have a problem in there, then you can’t call the doctors. You’re in there and you can’t come out. You need to have a guy in there with you who is trained to help you,” says Pegg.
All divers are required to pass a comprehensive medical exam before they can get their commercial diving license. They must be seen by a physician who is knowledgeable in diving medicine, and their medical fitness must be evaluated annually or every two years (depending on age and jurisdiction). The most important body system for divers is the cardiovascular system — they need to have a good heart and lungs, says Korol.
“We’re doing something that has a lot of exertion involved with it,” he says. “We’re climbing out of water wearing sometimes 150 pounds of equipment, so you’ve got to be physically capable and strong and having stamina when you’re under water doing a repetitive task. Maybe you’re sawing something under water or moving sandbags.”
The use of prescription medications, recreational drug and alcohol use, obesity, lack of physical conditioning and smoking can also affect safety while diving.
It is not safe for individuals with diabetes, heart disease or coronary artery disease to dive due to their respective risks of suddenly losing consciousness, having a heart attack or experiencing decreased blood flow to the heart. Asthma and high cholesterol are other medical conditions that can affect an individual’s ability to dive safely.
It’s not just health issues that need to be considered for divers, it’s mental health as well. Korol tells his students that diving is 50 per cent psychological.
“When we get into certain areas, a diver can really work themselves up into a panic. It’s like when you’re at the lake in the summertime and you go for an evening dip and you feel a weed touch your leg and your mind starts going. A diver can psych themselves out pretty quickly and easily.”
There’s no formal psychological assessment required for divers, but doctors will now interview the applicants and ask why they want to go into the profession. If they have a thrill-seeker personality, are prone to taking unacceptable risks, are upset easily or are panicky and jittery, they are not best suited to the job.
“We want people who are calm, cool and collected… Somebody who doesn’t rattle easily, is cool headed and can problem-solve on the fly,” Korol says.
The culture of safety in the commercial diving industry in Canada varies province to province, says Griffin.
“What’s happening in some of the provinces in the East Coast, New Brunswick and Nova Scotia is as far as I am concerned a national embarrassment. Quebec is excellent, Ontario is excellent, best regulations going, B.C. is catching up, Western provinces are still kind of the Wild West, but they’re all getting there little by little,” he says. “Unfortunately, what it takes is accidents to draw attention to it, and that’s been the problem.”
All commercial diving outfits and independent divers need to be up to speed on health and safety legislation in their respective jurisdictions, because their lives depend on it.
“It’s getting through to the old-timers out there that the regulations are written in blood,” says Korol. “There’s a reason for these regulations and standards and it’s because people died not following them.”
This article originally appeared in the February/March 2019 issue of COS.