Chemical containment incidents serve as an important reminder that mechanical integrity, inspection discipline and maintenance rigor remain critical safeguards in hazardous operations.
A vertical chemical vessel in hazardous service does not typically fail without warning signs. In many cases incidents are preceded by a combination of factors such as abnormal heating, deterioration, deferred maintenance, inspection gaps, or operational pressures that develop over time. By the time the public sees the event, the underlying integrity challenges have often been developing for some time.
The real challenge starts long before a leak
One of the key industry challenges is ensuring that code compliance is supported by effective in-service inspection and ongoing maintenance throughout the asset lifecycle.
A vessel may have been built to code, certified at the time of construction and still become a serious liability if in-service inspection is weak or maintenance is reactive.
For new construction in North America, the core design framework is typically:
- ASME Section VIII, Division 1 for pressure vessel design and fabrication, with ASME Section II for materials, ASME Section IX for welding qualifications, and ASME B16.5/B16.47 for flanges.
- ASME B31.3 for chemical process piping connected to the vessel.
- If the equipment is an atmospheric or low-pressure storage tank, API Std 650 governs new construction.
Pressure relief design must satisfy ASME Section VIII requirements so pressure cannot rise beyond acceptable limits, including scenarios involving external heat or fire exposure. That is critical for heated chemical service, because overpressure, vapor generation and thermal stress can quickly turn a small defect into a loss-of-containment event.
In-service inspection must remain rigorous
The real question is not whether the vessel was built to code, but whether the owner proved it remains fit for service.
For pressure vessels in chemical service, the governing inspection code is API 510, which covers in-service inspection, repair, alteration and rerating of pressure vessels and their pressure-relieving devices. For atmospheric storage tanks, API 653 governs inspection, repair, alteration and reconstruction.
API 510 and API 653 require:
- An inspection plan based on credible damage mechanisms (corrosion, cracking, thermal distortion, nozzle loading, gasket degradation, etc.).
- External and internal inspection frequencies aligned with the actual risk and service severity
- Use of API 579-1/ASME FFS-1 for fitness-for-service assessments when flaws or anomalies are found.
- Use of API 580/581 for risk-based inspection planning where resources must be focused on the highest-consequence assets.
Inspection programmes should be capable of identifying precursor conditions and deterioration mechanisms before escalation occurs, not simply demonstrating that inspections were completed on time.
Maintenance is where prevention happens
Maintenance in hazardous chemical service is fundamentally about preserving containment.
That means:
- Relief devices, vents, alarms, temperature sensors and high-level protections must be tested and maintained under the same discipline as the vessel wall.
- Any sign of leakage, distortion or temperature excursion must be treated as a technical signal rather than a nuisance.
- Deferred action is one of the most common habits behind serious incidents. Small defects are rarely small for long.
Many incidents are not caused by one catastrophic mistake. They can result from a combination of smaller unresolved issues that compound over time. A minor seep becomes a crack. A crack becomes a leak. A leak becomes an emergency.
Certification and competency matter
Another important reality is that credentials and competency must remain current. An inspector’s knowledge and qualifications must remain current as codes, technologies and operating conditions evolve.
API 510 is an individual certification, but it is not a one-time badge. The recertification requirements now include:
- 24 CPD hours for certifications expiring on or after January 1, 2025
- Continuing inspection experience and periodic quiz requirements at the six-year point
That matters because codes evolve, failure mechanisms change, and real-world lessons must change how inspectors interpret abnormal conditions.
Independent oversight provides valuable assurance
An internal team can sometimes become too close to production pressures or accustomed to abnormal operating conditions.
A properly qualified third-party inspection organization brings:
- Procedural discipline and independent technical oversight
- Additional objectivity when assets show signs of abnormal heating, leakage or cracking
- Support for fitness-for-service reviews and integrity decision-making
For hazardous chemical service, independent oversight can play an important role in helping organisations challenge assumptions and reduce complacency risks.
The lesson for operators
The industry already understands the risks associated with hazardous chemical service.
The broader lesson is the importance of maintaining strong inspection, maintenance and operational discipline before small integrity concerns escalate into larger events.
Facilities handling hazardous chemicals need inspection programmes that function as proactive challenge mechanisms, maintenance teams that are empowered to act early and leadership teams that are willing to prioritise integrity and operational safety alongside production demands.
Future incidents will not be prevented by slogans alone. It will be reduced by technical rigor, proactive maintenance, operational accountability and early intervention when warning signs emerge.
Even relatively small loss-of-containment events can provide important lessons for industry.
LRQA supports operators globally with independent inspection, certification and asset integrity services aligned to recognised industry codes and standards, including ASME-related inspection and welding assurance services.
