Skip to content

The world below

By Amanda Silliker
| www.cos-mag.com

About 15 years ago, a man was working on a sewer line around a butcher building in Manitoba. At the time, the plant let all the unused cow guts go down into the sewers, so the worker was up to his hips in cow innards trying to complete a repair job.

“After that, the guy took a pay cut and went and became a snowplow driver,” says Troy Winters, senior health and safety officer at the Canadian Union of Public Employees in Ottawa.

Rats, syringes, tampons, dirty diapers and human feces are just some of the things sewer workers face on a daily basis. Basically, anything that gets flushed down a system — from the toilet, kitchen sink or industrial workplace — sewer workers will come in contact with.

“You get some pretty strong and unpleasant odours and substances and it’s not the easiest thing,” says Michael Pigott, works superintendent at the City of Charlottetown. “You need to have a strong stomach. It’s not for everyone that’s for sure. These guys have their jobs cut out for them.”

Aside from doing stomach-churning jobs, workers who work on sewer lines — such as inspectors, maintenance workers and technicians — complete high-risk tasks every day.

“It’s probably one of the most dangerous (jobs) that our CUPE members do,” says Winters. “There’s lots of potential hazards down there and you never know what is down in the manhole when you open it up.”

Workers exposed to sewage face a significantly increased risk for airway symptoms, chronic bronchitis, toxic pneumonitis (inflammation of lung tissue) as well as central nervous system symptoms such as headaches, unusual tiredness and concentration difficulties, according to the 2002 report “Work Related Symptoms Among Sewage Workers: A Nationwide Survey in Sweden” published in Occupational & Environmental Medicine. Further, they also face increased risk for gastrointestinal symptoms and joint pains.

Biohazards

There are lots of potential infections that can come from working around whatever gets flushed down the toilet. The most serious viral risk for sewer workers is hepatitis and the most serious bacterial risk is tetanus.  Workers need to make sure their vaccines are up to date.

The City of Charlottetown provides hepatitis A and B vaccines as well as tetanus vaccines for its workers who are exposed to raw sewage, says Pigott. They are also supplied with all kinds of personal protective equipment (PPE) — gloves, boots, coveralls, half-mask respirators, rain suits, hard hats and eyewear — to protect them from the biohazards.

Respirators are particularly important to ensure nothing can splash up and get in the nose or mouth.

“The respirators we use are good quality with the cartridges on them and we are fit tested for them. We have a good secure fit on our face — which is really important,” says Blaine Parkman, utility foreman at the City of Charlottetown.

Workers should keep all their equipment at work so they don’t bring any potential contaminants home. When designing the utility stations, there should be a clearly defined “dirty area” where workers can change out of their PPE and a “clean area” where they can put on their street clothes to avoid contamination, says Winters.

“If you think through the flow of materials, where the equipment is coming from and going to, a few basic steps will certainly help decrease the chance that somebody  will be re-exposed to something after it was supposed to be cleaned,” he says.

And the workers’ trucks should be considered as contaminated as the work area, so when they change out of their PPE back in the station, they have to make sure not to get back in the truck again.

Confined spaces

Manholes, lift stations and sewer lines themselves are all confined spaces, which come with many concerns. These spaces can sometimes become deficient in oxygen due to oxygen being used up by the decomposition process and combustion processes, such as cutting and welding. Oxygen-deficient atmospheres may cause a person to feel lethargic and potentially lose consciousness.

In Alberta, for example, the minimum concentration of oxygen required in a worker’s breathing air is 19.5 per cent by volume. Below this level, air supplying respirators must be worn.

Hydrogen sulphide (H2S) is a highly toxic gas that can be present in sewers. It can be created by the decomposition of organic matter. Low concentrations have a smell of rotten eggs, but the odour is not present in higher levels. Concentrations of H2S above 500 parts per million (ppm) will cause unconsciousness in a few seconds and can lead to death if action is not immediately taken.

In April 1969, three workers in Portage La Prairie, Man., went to a sewage lagoon to check a valve on a feeder line. One worker entered the valve chamber and collapsed. The second worker went in to rescue him and also collapsed. The third worker called for help, but by the time the fire department arrived, the two workers had died. Air samples determined H2S was in excess of the measuring instrument’s upper limits.

Carbon monoxide — a colourless, odourless and toxic gas — is a concern in sewers due to the gasoline and diesel engines overhead. Exposure to concentrations exceeding 25 ppm may result in ringing in the ears, nausea, headaches and sleepiness.

“If we were to enter a confined space with some of these gases present, it could overcome us and the person entering the space could pass out and eventually, if the gases were strong enough and potent enough, it could cause damage,” says Pigott.

Gases or vapours that are flammable or explosive pose a serious hazard for workers in sewers. Methane gas — a byproduct of backed up or sluggish sewers — is one example as it is very flammable. Additionally, even though it is against the law, gasoline, oil, paints and solvents are sometimes flushed down into the sewer as a means of disposal either from residential properties or factories. Gasoline may also enter the sewer system from leaking underground storage tanks or inadvertent spillage.

Explosive hazards are the most concerning, says Randy Cowan, president of Cowan Consulting in Bowmanville, Ont.

“You can have all the protective equipment in the world on — you can have supplied air if there is a low oxygen content in there — but there’s going to be no protection from the explosive limit if something goes south pretty quickly in there,” he says.

The City of Charlottetown has a three-step process to test the air in a confined space to ensure it is safe for workers. Before the cover is even opened to the manhole, a universal pump probe (a wand-like attachment for the gas detector) is inserted through the access holes of the manhole lid to check for hazardous conditions, says Pigott. Once it’s cleared, the cover to the confined space is opened up and a remote gas detector is lowered into the structure that checks for oxygen deficiency, H2S, carbon monoxide and the lower explosive limit. As a final precaution, the worker entering the confined space has a gas monitor strapped to him. And if that monitor goes off for any reason — even if it’s just a low battery warning — the worker needs to get out of the confined space right away.

“We have been in situations where the monitors went off and we don’t hesitate to get extracted out ASAP,” says Parkman. “We don’t want to take that chance. Things can change very, very quickly down there. The sooner we can get out the better.”

Companies are required to maintain their air monitoring test records — which are recorded on confined space entry permits — for a minimum of one year. Many keep them for two years, which allows them to review trends in worker health.

“If a worker ends up being ill down the line, they can go back to those reports and say ‘What was the exposure?’” says Cowan.

If the gas detector alarms are sounding, employers should ventilate the space. Powered blower equipment must be used. According to the government of Alberta, ventilation must continue until:

• the oxygen content of the air is between 19.5 and 23 per cent by volume

• the concentrations of toxic contaminants are below their occupational exposure limits

• the concentrations of flammable contaminants are below their lower explosive limits.

The City of Charlottetown sets up a forced air system of fans that blow large volumes of air into the confined space and remain operational for the duration of the project, says Pigott.

“They do an air circulation and do that for a period of time and re-test the confined space to make sure everything is going to be safe.”

Wet environments

Slips, trips and falls are a common hazard among these workers because sewers are wet environments. Ladders going down into manholes or lift stations can be very slippery or rusted out, and the floors and walls can be slippery as well.

“When we are down in the manhole or well chamber, the conditions down there can be pretty bad, depending on where we are. There’s excess grease down there that you have to watch for especially on the bench of the manhole. It’s very slippery and there’s human solid waste and stuff like that — those are the things you really have to watch for,” says Parkman.

To mitigate this risk, workers move as much of the debris out of the way as possible, which sometimes means putting debris in a bucket and hoisting it up to workers at the surface, says Parkman.

 The City of Charlottetown also offers awareness sessions on slips, trips and falls.

“It’s a little bit of a refresher to our workers to keep an eye out (because) in this line of work, we get into quite a few of those hazards, more so when you get into a water main break or something of that nature,” says Pigott. “As soon as you get water spraying or flying all over the place… it becomes very slippery.”

Drowning is always a concern in spaces that are not fully drained, as is the case with a sewer. It takes little standing water or other liquid to create a drowning hazard.

“You can drown in an inch of water,” says Winters. “If you hit something and knock yourself out or lose consciousness because of a low oxygen atmosphere and land face down in sewage water, then you’ve drowned.”

To avoid an influx of water when workers are in the sewer, companies have systems in place that divert the water from one manhole to the next one down the line, says Cowan. This way, the water completely bypasses the workers.

Sewer workers face other hazards as well, such as vehicles overhead. Since manholes are generally located right in the middle of the road, workers need to take extra precautions. Utility workers need to take traffic control management training.

“It’s all about setting up a safe work zone for the workers to be in, whether it’s signage coming up to the spot, cones and they need a written traffic control plan, so it creates that safe area for them,” says Cowan.

 Noise created in a sewer — such as from cutting, grinding or welding — can be harmful because the sound reflects off the walls. According to the government of Alberta, noise levels from a source inside a sewer can be up to 10 times greater than the same source located outdoors.

“(For example) they might have a drill or boring tool down there to do some debris removal. Just imagine being in a small room with lots of echo and creating that kind of noise,” says Cowan.

Training is very important for workers who go down into sewers, and Cowan recommends a “spring startup” every year to act as a refresher.  This training should include air monitoring, atmospheric hazards, entry procedures, rescue procedures, duties of entrants, duties of attendants, as well as hazard assessments and restricted space assessments. 

At the City of Charlottetown, all new employees go through an orientation process on the organization’s policies and procedures. Existing workers are also required to go through this training once per year.

“It makes them aware of the various hazards that are in our work environment and how everybody needs to pull together, safety-wise,” says Parkman. “Sometimes people do forget things and when we go through this orientation, it just refreshes everybody.”

All sewer workers at the city must also undergo training around traffic control management, WHMIS, asbestos handling, first aid and CPR, slips, trips and falls and PPE. 

If there is an incident among City of Charlottetown workers, additional training will follow.

“For instance, if someone has a slip or a trip, every action has a reaction so we follow up with a bit of training to try and mitigate any future accidents,” says Pigott.

Comprehensive confined space entry training is a must for all sewer workers. They need to understand the hazards of the confined space, safe work procedures to perform their duties and how to properly use the PPE required for entry (full body harness and lifeline).

Training is also important for attendants at the top of the confined space. They have to know how to effectively communicate with the worker down below, says Cowan.

Confined space rescue training is also essential for those who would be involved if something were to go dramatically wrong, says Cowan. The rescue crew needs training on the specific equipment (tripod and winch system), PPE (self-contained breathing apparatus) and processes required to perform a rescue.

First-aid and CPR training is also crucial for the rescue team.

“There’s a four to six minute window without oxygen before permanent brain damage. If someone goes down in a confined space and we are relying on emergency services to come, they are probably seven to eight minutes before they are on site,” says Cowan. “For the safety of the worker, we need to have him on top of that hole before they get there.”

City of Charlottetown workers complete the confined space training and rescue at the PEI Firefighters Association every two years. The city also does its own in-house training every six months to keep people refreshed.

“We are in a field where we have to take safety very seriously… so the refresher training just keeps everybody alert and ready to go into action and perform a rescue if that problem ever arises,” says Parkman.

Over the past few years, safety has become an increased focus at the City of Charlottetown — a reflection of the industry as a whole, says Pigott.

“It’s gotten to the point where people are really being heard,” he says. “It’s better for everybody and a safer work environment.”

At the city, the workers are a close-knit group both during work hours and in their personal lives. They all work together to identify and address any red flags that come up and look out for one another on the job.

“Everyone has a part to play in safety and we all work together to make sure we accomplish it,” says Pigott. “ Injuries are all preventable, so why not prevent it?”

This article originally appeared in the April/May 2016 issue of COS.

Videos You May Like

Safety Tip — Confined space entry

Safety Tip — Confined space entry

Any confined space comes with many hazards
Roundtable on Confined Space - Rescue and Emergency Planning

Roundtable on Confined Space - Rescue and Emergency Planning

Panelists discuss some best practices in developing an effective confined space rescue plan.

Add Comment