New Safety Book Exposes Hidden Dangers in Sewers

Mar 3, 2017 8:15 AM ET

As featured in Impeller | Water News from Xylem

A deadly explosion at a wastewater plant in Florida led two Xylem employees on a six-year journey to improve the safety of wastewater workers. Their new book combines science with reports on some of the biggest accidents in recent history.

Impeller recently spoke with Amy Forsgren, a technical writer at Xylem, who wrote the new book Airborne Occupational Hazards in Sewer Systems with Kristina Brinck, an information designer at Xylem.

Why did you want to write this book?

The idea came in 2010, when I read about a horrible accident in Florida at a wastewater treatment plant. It was a completely unnecessary accident, where two people died a really horrible death. The plant had ignored some very basic safety procedures. They sent a crew to weld on top of a tank full of methanol without taking the right precautions, and the hot work caused a huge fireball.

I was so angry – it wouldn’t surprise me if steam was coming out of my ears. Then I ran into Markus Holmberg, the manager of safety at Xylem, and told him about the accident and how upset I was. He said, “What are you going to do about it?” So then Kristina and I decided to write a book about safety.

What did you want your book to focus on?

It evolved over the six years it took to write it. Instead of looking at wastewater treatment in general, we decided to focus on airborne hazards. For treatment plants, the most common hazards are the standard hazards that every industry has, like dangers from falling, electrocution, crushing by moving parts. There are already a lot of books covering these, not necessarily for treatment plants but for industries in general.

But the sewers have a very special atmosphere, because sewer water can contain methane, which is explosive, and hydrogen sulfide, which is highly toxic if you breathe it. Both of these are created as waste decomposes. We found that in a lot of safety books when they discussed these gases they would say, “They aren’t really a danger unless you have to work in a sewer.” We looked and there aren’t any books about the special circumstances for sewers.

Who do you hope reads your book?

Engineers for municipal water and wastewater systems, anyone who is going to send someone down into a sewer. We would like them to know the dangers of what they are sending people into. That is our main target. But also the chapter on hydrogen sulfide will be of interest to anyone doing occupational safety research on hydrogen sulfide, especially the statistical analysis we do. I think we are the first people in the world to summarize this information about hydrogen sulfide.

What did you learn about hydrogen sulfide?

What we did in our book is summarize all of the findings about biomarkers and hydrogen sulfide deaths from Japan and the US, which hadn’t been done before. Eight years ago in Japan, it became popular to commit suicide using hydrogen sulfide. Over 100 people killed themselves this way, almost exclusively young men.

But there were a a few accidental deaths as well. In one case a person went into the bathroom to commit suicide, and their parent jiggling the locked bathroom door was enough to let gas escape around the door. The gas is so lethal that the parent was also killed.

What we found is that a lot of people have died from hydrogen sulfide, and because it kills so fast it doesn’t show up at all in urine and often not in the blood. We can now say that we have data that proves that you can die from high levels of hydrogen sulfide and it will still not show up in an autopsy. This is important to know when determining the cause of a workplace death.

Read the complete story in the latest issue of Impeller 


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