Failure Files

In July 2006, 26 tons of concrete ceiling panels collapsed inside Boston's I-90 Connector Tunnel, killing one and injuring another. The NTSB investigation confirmed the cause: the wrong type of epoxy was used to anchor the hanger bolts. Fast-set epoxy creeps under sustained deadweight load. The right anchor would have held for decades.

In October 2020, corroded valve bonnet bolts at BASF's Geismar, Louisiana chemical plant catastrophically failed, releasing 554 pounds of toxic chlorine gas. The U.S. Chemical Safety Board confirmed the cause: the wrong fastener material in a chemical service environment. Here's what the right bolt choice looks like.

In May 2026, GM recalled 2,464 full-size SUVs — Escalades, Tahoes, Suburbans, and Yukons — because dealers had been installing the wrong wheel hub bolts on vehicles with 24-inch wheels. The NHTSA filing confirmed the root cause: the parts catalog didn't distinguish between wheel sizes. Here's what the physics of a bigger wheel have to do with bolt selection.

In 1985, a concrete ceiling collapsed onto a swimming pool in Uster, Switzerland, killing 12 people. The confirmed cause: the wrong grade of stainless steel — V2A (Type 304) without molybdenum — was used for load-bearing suspension rods in a chloride-rich pool environment, leading to silent, catastrophic stress corrosion cracking.

On April 22, 2021, one undertorqued connecting rod bolt destroyed a Washington State Ferry's diesel engine, started a fire, and caused $3.8 million in damage. The NTSB's confirmed finding is a masterclass in why torque specifications aren't suggestions.

On January 5, 2024, a Boeing 737 MAX 9 door plug blew out mid-flight because four retention bolts were never reinstalled after a factory rework procedure. The NTSB published its final report in June 2025. Here is what every maintenance professional and fleet manager should take away from this incident.

In 2013, 32 anchor bolts on the newly opened San Francisco-Oakland Bay Bridge snapped — despite meeting every spec they were given. Here's what hydrogen embrittlement, sustained load, and saltwater exposure taught the engineering world about fastener selection and the environment.

On July 17, 1981, two elevated walkways collapsed at the Hyatt Regency Hotel in Kansas City, killing 114 people. The cause traces back to a single design change involving threaded rods — and a load that nobody recalculated. Here's what it still teaches us about fastener selection today.