H2S release kills 1 at PEMEX Houston Refinery 2

[StressGuy]

Still developing, so no details on the cause, but local areas are still ordered to shelter in place.

PEMEX Refinery H2S leak

H2S is pretty nasty and most of us local have had to go through safety awareness training specifically for it. Many facilities require folks to wear H2S monitors where releases are possible.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[StressGuy]

Shelter in place has been lifted. Death toll now at 2 with another 35 injured.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[hokie66]

I wonder what the H2S monitors sense. The human nose is quite a good monitor, but maybe not good enough.

 

[3DDave]

https://www.emerson.com/documents/a...ng-its-danger-in-field-rosemount-en-72142.pdf

This paper has a description of several methods.

 

[StressGuy]

At low levels, you can definitely smell the rotten egg scent of H2S. However, at levels that rise to immediate danger, you nasal receptors get overloaded and you don't smell it anymore.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[Rabbit12]

What StressGuy said. High concentrations of H2S overwhelm the nose and you won't smell it. That's why you need an H2S monitor because you won't know you're in danger using your nose.

 

[1503-44]

I quit a job once when we finally drilled a well into a 4% H2S formation.
Not worth the risk.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[pierreick]

HI,
Good to read, very nasty chemical. You cannot rely on smell; you need to use calibrated sensor to assess the risks.

https://www.osha.gov/hydrogen-sulfide/hazards

Very familiar with this product in soda ash plant.
Pierre

 

[1503-44]

Even sensors will poison out.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Alistair_Heaton]

Was it Gabon that had alot of poisoned oil wells?

Gear coming back to the yards in Aberdeen was treated differently due to the possibility of H2S being inside it from some places.

 

[1503-44]

Turkmenistan and Indonesia, Malaysia seem to have quite a bit, but its not exactly in short supply. I just don't like it and don't want to be around it. Call me

 

[EdStainless]

The two plants that I did some work in that scared me;
one had a unit making sulfur chloride,
and the other had a hydrogen cyanide unit .....

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

I toured a geothermal power plant. Access to any low lying area was strictly forbidden. They reacted the H2S into elemental sulfur, enough to fill a 40ft bulk trailer every week. Quite an astonish amount for a plant that was operating at 15MW or so. Supposedly it was being shipped off to China to be burned.

 

[1503-44]

Lots of heavy metals at geothermal plants too. There used to be a huge yellow mountain range of S south of Houston. Don't know if it's still there. Could be a yellow flood zone by now. If you want to tour TX Wells with H2S content, here's the lists.

https://www.rrc.texas.gov/oil-and-gas/research-and-statistics/field-data/hydrogen-sulfide-h2s/

The field manager wanted to use an iron sponge vessel to scavenge H2S at the well site. Sooooo messy. And it supposedly likes to spontaneously combust. They didnt want to pay for a corrosion control program and the normal gas pipelines were keeping me busy repairing blowouts once a week anyway. Didn't want to find h2s there. They were in bankruptcy proceedings for the previous 13yrs, but had a good cash flow on cheap finding costs. The locals named the company Transylvania Natural Gas, cause they sucked blood from everyone. I think they payed us twice a month, because they knew if they paid us once a month, we would have money enough to buy a full tank of gas and get the hell out of there. I saved up.

I got drunk on toluene fumes from a barge once and nearly went swimming in the Mississipi. Arsenic? No way.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[georgeverghese]

While reversible effects from exposure to H2S show up almost immediately, there are the more sinister and irreversible effects from associated long term exposure to petroleum fumes. Often results in blood disorders such as leukemia. Sometimes takes years for these disorders to show up. As an example, this was common especially in children playing outdoors near oil fields around Basra, Iraq where associated gas was vented or poorly combusted at flares. We dont see operators wearing monitors for nasty BTEX exposure.

 

[TugboatEng]

So it wasn't the depleted uranium?

 

[waross]

Shelter in place for H2S?
Makes it easier to find the bodies.
As I recall several training sessions, head cross wind and leave the area.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[georgeverghese]

@Tug, There was and there still is depleted uranium exposure cases too, I would imagine. Not surprised many are reluctant to join the Armed Forces, partly for this reason. These BTEX exposure related cases were documented in a BBC doco (BP oilfields around Basra) some 2-3years ago.

 

[TiCl4]

Waross,

Shelter in place can be appropriate at times rather than evacuation. If concentrations in outside air are high or unknown, calling for an evacuation will cause most people to leave their homes, traversing the high concentrations to get to their cars.

Even if they make it to the car, driving in a car with the A/C on fresh air intake will port H2S directly into the cabin. Do you trust the general public to remember to turn the A/C off? Driving with A/C off is still near 1-2 air changes per hour. The general public is also not trained on how to avoid vapor plumes.

For events such as these, it may make better sense to stay indoors, close all building openings, and turn off A/C or heat until the event passes or until better data is obtained.

If all you were told there was a H2S leak at a nearby refinery with possible off-site impacts, would you feel comfortable ordering an evacuation? I wouldn't. Not until I had an idea of the size, scope, and expected duration of the leak. For a low-data initial decision, a shelter-in-place order is a better first step when data is limited, because that, at least, gets people out of the open air and into more protected spaces. Obviously, if the plant says the leak is huge and expects to kill thousands downwind, an evacuation order may be best to save the most number of lives.

All that to say, I believe an SIP order can be appropriate, and such public health decisions can be very, very difficult to make in real-time. I don't envy the person making such a decision.

 

[waross]

Hi TIC14
I agree with you for very large leaks affecting areas outside the plant.
My focus was instructions to in-plant personnel.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!