"Boiler Tank" (sic) explodes in Mexico Tequilla Plant 9

[MJCronin]

https://www.dailymail.co.uk/news/ar...o-leaving-six-workers-dead-three-injured.html

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SIX DEAD --- Many injured - an OSHA preventable, yet repeated tank accident
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Looks like somebody was welding on a flammable liquid FB storage tank ...We shall see

"Emergency Relief Vents" .... we don't need no stinkin' Relief vents on our repurposed tank !! ...

https://www.hazardexonthenet.net/article/206633/Explosion-at-Mexican-tequila-plant-kills-five.aspx

(Expect a lot more of this in the continental USA if the Repubs win in November ... and destroy OSHA & CSB)

Your thoughts ??



MJCronin
Sr. Process Engineer

 

[Alistair_Heaton]

https://www.scotchwhiskyexperience.co.uk/about/about-whisky/whisky-making/

This how we do Scottish whisky

I believe the cheaper fake whiskys will pasteurize and cool in the same tank as the fermentation.

 

[3DDave]

Almost certainly they drained the tank to make the repair, filling it with typical 20% Oxygen atmosphere and a suitable amount of remaining alcohol and didn't bother to rinse it out with water and ventilate the remaining explosive mixture.

Instead they built a fuel-air bomb and set it off.

OSHA isn't required - high school chemistry class is.

 

[LittleInch]

And breathing in that mixture isn't going to help you with making good decisions....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Heaviside1925]

Almost certainly they drained the tank to make the repair, filling it with typical 20% Oxygen atmosphere and a suitable amount of remaining alcohol and didn't bother to rinse it out with water and ventilate the remaining explosive mixture.

Could be. Or they could have rinsed in out with cold water and couple inches of water were left on the bottom of the tank. An LEL reading was taken, all good! What wasn't considered was the % of alcohol still in the water on the floor. The welding combined with some nice Mexican sun, heated up the vessel and water/alcohol mix remaining on the floor of the vessel until the LEL was reached and boom. There could have been safety protocols in place and followed, unintended and unforeseen events do occur. I'm not saying this is even possible (chemE's feel free to pile on), but any event like this can serve as a reinforcement of known safety practices but sometimes they can also serve as a learning tool to prevent future catastrophes.

 

[TiCl4]

Heaviside1925,

A residual alcohol/water mix still should have shown up on an LEL meter. I've seen a reference that beers above 3.5 ABV% have a flash point of 100F-200F, meaning to be flammable on a hot day there would need to be at least 3% ABV in the tank. I guess the wide range depends on whatever properties exist in the beer. The LEL of ethanol is 3.3%, so a 1% reading on the LEL would be .033%, or approximately 330 ppmv (maybe up to 1000 ppmv, depending on what the LEL meter calibration factor is). Either way, the vapor pressure of 3% ethanol in water is high enough that something should have shown up if it were in the tank already.

I don't know their hot work procedure, but any tank that typically contains flammable materials upon which we would be welding would be continuously monitored during the hot work, not just at the outset of the work.

 

[Heaviside1925]

TiCl4 Thank you. I guess my point was, there could have been measures taken to ensure the tank did not contain flammable material but did not consider other factors. Sadly, most times, it's just complacency or ignorant people doing ignorant things and this very well maybe the case, but I am always curious whether there were unknown factors at play and that can serve as a learning moment.

 

[Alistair_Heaton]

Hot works on tanks in Aberdeen caused quite a few changes of pants in the 80's.

Then they went extreme with the work card processes for pretty much everything post piper alpha.

It's now at the point you get a written warning for not using the handrail going up stairs.

 

[1503-44]

Safety regulations stricken, due to judge determining there was a failure to do proper cost benefit analysis.

So it seems that safety can now be judicially compromised due to an insufficient (unknown, or faulty, etc.) cost benefit calculation.

https://www.ogj.com/general-interes...rule-because-of-faulty-cost-benefit-analyses?

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

 

[JStephen]

There's always been a cost/benefit aspect to safety, although not always calculated, that's not just "now". If it's something obvious like blowing oneself up, no need for calculations. If you're wondering whether you should regulate Gizmo X in automobiles at a cost of $1,000 per car, when it will save 0.001% of accidental deaths, well, that's where the cost/benefit comes in.

 

[FacEngrPE]

The event occurred in Mexico. Granted the law may not be enforced consistently in Mexico, but Pipeline and Hazardous Materials Safety Administration (PHMSA) is an Agency of the US Department of Transportation.

Failure to follow proper procedures has resulted in federal regulations being canned by US courts a number of times. I chose to blame politicians that write defective law when this happens. Political problems rarely have purely engineering solutions.

It's time for comic relief.

https://youtu.be/BKorP55Aqvg

https://youtu.be/mokllJ_Sz_g

 

[3DDave]

All the court is saying is that the costs to society must outweigh the benefits to the company.

So, if there is a million dollar loss to society because a bunch of children died from 80% burns to their bodies and it would cost the company more than a million dollars to prevent that, the rule is struck down.
---
Edit: from the article:

PHMSA issued the sweeping pipeline safety rule in response to congressional mandates and recommendations from the National Transportation Safety Board (NTSB) after the 2010 San Bruno, Calif., natural gas pipeline explosion that killed 8, injured 58, and destroyed over 35 homes, and a 2010 oil pipeline rupture in Marshall, Mich., that spilled up to 1 million gal of crude oil into a tributary of the Kalamazoo River.

Apparently the court is OK with that happening again.

 

[1503-44]

Yes. My point exactly. A safety regulation was stricken by a judge who has no clue as to what removal of that safety regulation means in terms of safety (no other reason mentioned, apparent or implied in the article here), because s/he was only concerned with the cost benefit ratio (which still remains unknown, because the judge considered it faulty). This is regulation by judiciary, those least qualified to do so, and imo, abject stupidity. The regulation should have been left in place at least until a proper cost benefit ratio was determined, at which time it should be reevaluated in terms of cost benefit and the appropriate risk management matrix.

As it is today, Americans appear to be left exposed to what the regulating authority deems is a risky use of this welding practice on high pressure pipelines.

I agree that there may be times when obvious is obvious, but there are cases where obvious is not always obvious. Complex systems often have no obvious effects at all until "emergent behaviors" are discovered. This is one of those emergent behaviors where the frequency of the welding was once thought to have no effects whatsoever, but the subsequent recent data has shown otherwise. At this time it may pay to be conservative and follow these regulations until further evidence is acquired, but the judge says, "No. Do not worry. I don't know shit about welding, but it looks good to me."

I am not comforted.

So, what do we do today? Continue with our risky welding practice, contradicting latest findings? If the pipeline fails, will this judge pay the costs? Who will be liable? How long will it take to resolve this issue. What do we do now? Our own study? Make and follow our own procedure? If it doesn't work, are we liable. If we use the most Conservative approach, then the judge has done nothing, but confuse the issues at hand. The judge is in control. The lawyers make money. We are at risk. Perfect solution.

Defective laws can be a problem. If its a legal issue let the lawyers correct it. If its and engineering or safety defect, let the engineers correct it and amend the law. An independent determination by a judge is not an answer to either question. It only prioritizes political "solutions" rather than those based on other considerations, such as safety and integrity. This example, I think proves that conclusion. "Strike the regulation." Where is the safety in that? Do you feel better about a pipeline crossing your land because it may be cheaper? How did this judge help you? Did this judge make a just decision. I don't know. He didn't even have a good cost benefit analysis to make that decision. Now I don't know if the risk was justifiyingly small to make a cost reduction worth it or not. Not that I was going to save any money either way. Its just arbitrary judicial regulation. How is that better?

TCi4, I have not got it backwards. I think I'm same as you. ASME engineers wrote codes for all this stuff. B31.4 and 8 for pipelines. No problem for me. That's how it should be. Those codes have been mostly adopted into the CFR pipeline regulations word for word. PHMSA tends to make clarifications, rather than new code. The biggest difference is that CFRs are often 20yrs behind the times. Mostly because of recent polarisation, nothing can hardly be accomplished by Congress in the way of writing any new law, or what is written is watered down to nothing. For example, the new regulatory requirements are safety and integrity heavy to correspond to ASME B31.4 and .8 changes that have not yet made it into CFRs, because pretty much the pipeline industry can cut or keep bits they don't like or want out of it even as the procedure is now, and even if those were written by their very own engineers working in cooperation with ASME. And company lawyers are objecting to EVERYTHING they possibly can, regardless of who wrote it. I'm sure you have noticed that "Object to everything. Nothing new. Nothing additional. Take it back 50 yrs." is the new SOP.

I am all for engineers writing codes that get adopted as law. That's the only thing that makes technical sense. What I object to is judges cutting it up however they like based SOLELY on THEIR OWN INTETPRETATIONS. That's judicial regulation. And IMO, far worse then defective clauses that sometimes are the result of the logical process we have had up until now. Those can usually be corrected while temporary guidance is provided by regulating authorities. Not now. All stuff has the potential to be countered by other courts and delayed years and years until SCOTUS blesses us with their final opinions. We see how well that's not working. When it comes down to political vote, let's see how high engineering competency, system integrity and public safety weigh in.

There are no more engineering clarifications. Everything has become subject to "political clarification".

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

 

[zeusfaber]

All the court is saying is that the costs to society must outweigh the benefits to the company.

That's quite interesting. For comparison, the position in the UK is that a risk reduction measure should be enacted unless the cost of doing so is grossly disproportionate to the value of the reduction in risk. There isn't a set-in-stone definition for "grossly disproportionate" - our policy was to apply a factor of twenty.

A.

 

[1503-44]

I believe 3Ddave was being fecicious, but that can easily be the result of this SCOTUS ruling. It puts to sleep the logic of the map you mention.

Before it was compare costs of mitigation to the sum of probability of occurrence of each risk x expected value of corresponding damages. Build it only if costs were still acceptable. (You could still make a profit). You could put a value on deaths of some sort, if it helped you decide. Or solve for the value you place on death, if you had a Max cost of risk dollar figure and then see if the lawyers thought you could keep payouts under that figure. Naturally there were always concerns on that particular value, as it is rather subjective. It was typically whatever value the lawyer told you to use. In the Lowel Massachussetts pipeline explosion, which damaged some 131 houses and killed one person, it turned out to be $ 1 billion, loss of face and stock value, company forced to sell their state gas system distribution operation and vacate the state. All for improper supervision of repair work contractor. Boeing is still not sure of what their mistakes cost. Many billions above the Lowel disaster.

Theoretically Boeing can ask a judge to vacate any air worthiness directive that might apply to Max8 recertification and if the judge agrees, they're done. It flies today. All regulations are up in the air now. What will the judges decide tomorrow? Next week Will? Will they decide the same in each court? When will we know the answers. What do we do about it today. All unknowns. We are flying blind.

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

 

[FacEngrPE]

Paper on - Cost-Benefit Analysis in Federal Agency Rulemaking dated March 8, 2022 - attached. This is not a new requirement.

https://www.ogj.com/general-interest/government/article/55135346/federal-court-throws-out-parts-of-new-pipeline-safety-rule-because-of-faulty-cost-benefit-analyses[/URL]]A federal appeals court told the Pipeline and Hazardous Materials Safety Administration to rewrite several sections of a major pipeline safety rule in effect since May 2023.

The three-judge panel of the US Court of Appeals for the District of Columbia Circuit found that PHMSA, part of the Transportation Department, failed to follow the Administrative Procedures Act’s (APA) requirement regarding cost-benefit analyses in 4 of the 5 standards challenged by a natural gas pipeline trade association.

The court found that the rule making was defective, this is something they are supposed to do. The agency can repair the rule, and reissue it. It was not just the cost benefit analysis, part of the new rule was not advertised correctly (per the cited article).

I wounder how this sort of situation works out in Mexico?

 

[mfgenggear]

What is the number 1 common sense rule when cutting or welding on a tank that had combustible liquid.

 

[1503-44]

Worker safety is a problem everywhere. Especially where workers can be easily exploited, or have a sense of duty to complete an assignment even when conditions may not be entirely safe to do so. Looking back, I can see I fell into that trap more than once. Things that I simply should not have done, but felt compelled to do to complete my assignment. Swinging from platform to workboat on the Tarzan rope in 6 ft waves and a 30-50mph headwind wasn't too smart. Hit the side of the boat the first time. I even did it again. The deck hands pulled me in. Babysitting a control valve for a month in the middle of guerilla territory 50 miles from town at the height of the Colombia war in 1986. Trying to reach a valve too far off the tank rooftop swinging from a rope 50ft in the air. Getting in a helicopter that was obviously overloaded and taking off in thick fog. I worked at one gas company that had so many pipeline explosions (1-2/week), due to complete disregard for corrosion control, that I immediately quit when we finally drilled a well into a gas field with a lethal H2S content. And that's only the stuff that happened at work.

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

 

[mfgenggear]

1503
As a youngster I did bone head mistakes , and some how I survived. But never work related.
In this case management should be prosecuted for allowing a very bad dumb
Mistake. Mexico while I don't know for sure may or may not have more relax laws.
But a work related accident like this killed people.
There is a reason seasoned skilled lead men or women are in charge.
And safety rules are in place.
Accidents happens but this was negligence.

 

[1503-44]

The thing is, back then I thought I was supposed to do those things. I never thought I should have said "no way in hell I'm doing that." So guys, just don't do that kind of stuff.

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