Chemical Process Safety (PSM/RMP)

The history of NH3’s IDLH Limits

The history of ammonia’s Immediately Dangerous to Life or Health (IDLH) levels is a classic example of how occupational safety standards evolve as toxicological data becomes more refined. Since the concept was first introduced in the 1970s, the ammonia limit has undergone significant downward revisions based on a better understanding of acute human tolerance.

Styrene Tank explosion and fire on chemical tanker Stolt Groenland (Report & Video)

On 28 September 2019, a cargo tank containing styrene monomer on board the Cayman Islands-registered chemical tanker Stolt Groenland ruptured due to runaway polymerization. The catastrophic rupture released a large quantity of vapor into the atmosphere, which subsequently ignited. Fire-fighting efforts by the emergency services took over six hours and involved more than 700 personnel

OSHA Citation Report: Standard 1910.252 (General Requirements)

Reporting Period: October 2024 – September 2025 This report summarizes the enforcement activity for 29 CFR 1910.252, which covers general requirements for welding, cutting, and brazing. The data reflects current penalty amounts and identifies the economic sectors most frequently cited. Executive Summary During the specified period, OSHA issued 160 citations across 115 inspections, resulting in

Double Fatality – Welding on ATM Flammable Storage Tank (GRAPHIC)

There are very few instances where OSHA uses such clear language, but in 1910.252(a) they use the phrase “absolutely certain” and for good reason! This explosion occurred at a wastewater treatment plant in the city of Gumi, South Korea, on October 19, 2016. 1910.252(a)(3)(i) Used containers.No welding, cutting, or other hot work shall be performed

Is trans-loading a HHC/EHS exceeding its TQ a PSM or RMP “covered process”?

I have had a numerous discussions with companies regarding this new push for “trans-loading”. Trans-loading is defined as: “Transloading means the transfer of a hazardous material by any person from one bulk packaging to another bulk packaging, from a bulk packaging to a non-bulk packaging, or from a non-bulk packaging to a bulk packaging for

Know your LEL Detector’s Limitations (Humidity)

Low humidity makes most LEL (Lower Explosive Limit) detectors read lower than they should, because catalytic‑bead sensors depend on moisture for heat transfer and baseline stability. This can lead to under‑reporting of gas concentration, slower response, and—in extreme dryness—temporary sensor desensitization. Below is a clear, technically grounded explanation based on how LEL sensors work and

Process Safety Alarms and the “Wolf Syndrome”

“Wolf Syndrome” in the context of false alarms refers to a pattern where repeated false alerts cause people to stop responding, even when a real danger appears. It’s based on the classic “crying wolf” concept and is widely discussed in psychology, emergency management, and safety‑system design. The term is not a medical diagnosis—it’s a metaphorical

Improper repair of “stove” at steel mill leads to catastrophic failure

The dome failed at a repair patch that had been improperly welded and did not provide the minimum thickness needed to contain the dome’s operating pressure. The steel mill’s mechanical integrity program lacked effective inspection and weld repair practices, contributing to the incident. In iron manufacturing, a blast furnace operates at high temperatures to convert

NIOSH 2026 Request for Information (RFI) on NH3 IDLH values

In March 2026, NIOSH issued a formal request for information to update the IDLH Value Profiles. While ammonia has an established IDLH of 300 ppm, the agency is seeking new toxicology and human health effects data to refine these values. The Focus: The RFI specifically looks for “weight-of-evidence” data on how chemical modes of action—such

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