Hazardous Materials

Consider Human Error and Domino Effects (EPSC Learning Sheet July 2025)

At an Ethylene unit in the Czech Republic (2015), when swapping over cooling water supply lines during a flowmeter calibration, the operator made a simple mistake. While intending to open valve #3 on the spare supply line, he closed the identical valve #2 instead, shutting off all cooling water to the Light Ends columns. A…...

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BLEVE in Sidney, MT on 6/25/2025

A picture-perfect BLEVE caught on drone cam. A storm chaser captured this fire and BLEVE while traveling to chase a storm in Canada. This was in Sidney, MT, and may be the best training video showing a BLEVE (he has even slowed the footage down so we can see it in slow motion)…. Membership Required...

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Why NH3 must be evacuated to “reclassify” a Condenser from a PRCS to a NON-PRCS

I have debated this many times and finally just gave up on the industry to do the right thing. And yes, there is a line item in NFPA 350, that I have requested the NFPA to address. But for me, in all my years, we would evacuate the NH3 from the condenser coils and lock…...

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PSV inlet pipe failure (6# NH3 release inside Machinery Room)

A piping fitting failed, resulting in the release of approximately 5 pounds of ammonia (NH3) in the machinery room. The nipple (fitting) between the oil separator and its relief valve cracked and failed to hold ammonia in the piping, resulting in the activation of the exhaust ventilation system. Fittings made of certain materials are incompatible…...

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Another “Torque Matters” event (16-pound NH3 Release from Oil Separator)

In an ammonia refrigeration system, ammonia in a gas state is compressed from the compressor to high-pressure, high-temperature ammonia gas. The compressed gas heats as its pressurised. The hot gas enters an oil separator, where the ammonia gas and compressor oil is separated so that oil is not carried over with the ammonia gas to…...

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E-Stops: Process Safety vs Machine Safety

I see this all the time… E-stops on Hazardous Materials process located at the point of the expected/intended failure point, such as a loading/unloading station. Many safety pros have experience with E-stops as a safety device for machinery/equipment, in which the E-stop is located at the point of potential entrapment inside the machine/equipment. Even ANSI…...

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A worker dies cutting a hole in a tank for a level indicator

At 1:00 p.m. on December 10, 2024, Employee #1, 28, was using a torch to heat the steel lid of a tank, intending to cut a hole for installing a level indicator. The flammable gas inside the tank ignited when the torch was applied, causing the tank to rupture. The employee’s lanyard was cut during…...

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What does AI say about the old saying, “three threads showing” for nuts and bolts on our process?

I have this debate regularly with facilities where I find “short-threading” on their flanges/manways, etc. This phrase is from an old pipe-fitters manual, and it’s what I was taught in 1993 when I entered the chemical process industry and PSM/RMP covered processes. Today, “full engagement” is defined at the bolt/nut being FLUSH. So I asked…...

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Flammable Refrigerant Fatal Explosion (Graphic)

I have railed against these refrigerants and all the code/standard revisions to make them easier to use.  Now, OSHA has adopted the 7th edition of the GHS, and we now have Cat 1A and 1B. These flammable refrigerants fall in the 1B’s because:… Membership Required You must be a member to access this content.View Membership...

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ASME 1949, CGA 2.1, and NH3

It not often I come across a 70+ year old PV still in pristine condition. Below is the name plate for this vessel and it carries an interesting code compliance story. As I said, it’s not often to find a NH3 storage vessel this old and because of its age, it carries some SPECIAL PRV…...

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Temporary SOP, Car Seals or BOTH?

What would you require for this bypass around a safety critical valve? Temporary SOP, Car Seals or BOTH? The automated valve is the Emergency Shutoff Valve tied to a Hi-Hi Interlock on an above-ground atmospheric flammable liquid storage tank. The LOPC/Over-Fill event occurred because the worker filling the tank was “shorthanded” that day and had…...

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“Pouring Conduit” in my HAZLOCs (Video)

What exactly does this phrase mean, and how is it done? This is a CRITICAL aspect for conduit in our Hazardous Locations (HAZLOC). It is something we should be checking (sampling) in our conduit runs in our HAZLOCs. The video below is by far the best I have ever seen that explains why we “pour…...

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