Posted on 08/03/2025 10:41:39 PM PDT by nickcarraway
Four workers have died in Japan after falling into a manhole near Tokyo as they inspected sewage pipes, authorities said on Sunday (Aug 3).
The incident comes after a huge sinkhole swallowed a truck driver near the capital in January after a road collapsed because of corroded sewage pipes, sparking a nationwide inspection.The workers - all men in their fifties - were checking pipes in the city of Gyoda, north of Tokyo on Saturday, when one fell down the manhole, followed by three more who tried to save him, the local fire department told AFP.
The department said rescuers detected hydrogen sulfide - a gas toxic in high concentrations - coming out of the manhole.
(Excerpt) Read more at channelnewsasia.com ...
No, at that concentration there was instant loss of sense of smell and death in the next breath. It really is that dangerous.
What makes H2S, other than its toxicity, is it is heavier than air. When there is a release, particularly at a wellsite, the concentration can be more than any human can tolerate and doesn’t dissipate without a steady wind. Wellsites generally have a burn tower that runs from a separator after the usable gases come out of the wellhead and burns off at an elevated position. Resulting gas is Sulfur Dioxide, which is just as toxic as H2S but much lighter than air.
I see. So the levels should be relatively stable across time. Because what the company is saying in their defense is that initial measurements were anywhere from 30-80 and ended up at 150.
No, levels can change rapidly, that is another aspect of the danger of it. With 30 - 80 ppm no one should have been anywhere near that damn manhole.
There are safe ways of working in higher that normal H2S environments, lack of breathing apparatuses is NOT one.
Like what you said. In thr oilfield, if someone goes down to an H2S release, you leave him. Only when someone qualified and equipped in (thanks to fidelis) SCBA use is sent in can anything be done.
Tripod and harness retervial until SCBA equipment and operator arrives are the only way I know and it has to be fast
You dont ever expose someone to it intentionally, not until SCBA is in play, and only with saud gear being used.
We had safety people sampling and retrieval gear ready every entry I ever made. I’ve been in well pits, utility tunnels, boiler mud drums, etc. it’s not anything to take lightly. Your reaction reflex if you see a coworker go down is get in there and help. In oxygen deficiency conditions it’ll kill you and the other guy quicker than a fast train. Safety has to be first. IMO. Regards.
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