CSB Publishes Report on Acetic Acid Release in 2021 La Porte, TX Incident

Yesterday, the US Chemical Safety and Hazard Investigation Board (CSB) posted a link to their report on the investigation of a 2021 acetic acid release [removed from paywall] at the LyondellBasell La Porte Complex in LaPorte, TX. The CSB reports that the inadvertent removal of pressure retaining components of a plug valve caused the release of 164,000 pounds of high temperature (238˚F) acetic acid mixture, killing two contract workers and injuring several others. The Board identified two major safety issues and made six recommendations to industry and technical organizations.

According to the CSB, contractor employees were working to fix a leak on an in-service line in the acetic acid unit at the facility. During that work they needed to remove the actuator from a plug valve on a pressurized line. Instead of removing the bolts retaining the actuator unit, they loosened the bolts holding the pressure-retaining valve components.

Citing similar incidents with plug valves, the CSB notes that recurrence of these types of incidents points to the need to further re-design plug valves so that it is more difficult to remove pressure-retaining components while attempting to remove actuating equipment.  Additionally, the CSB reported that both the company and the contractor considered the removal of the actuator a simple task and did not provide the work crew with any sort of procedure or training and did not adequately assess the potential risk of the operation prior to commencing work.

The CSB made six recommendations to help prevent similar incidents in the future:

2021-05-I-TX-1 LyondellBasell La Porte Complex - Update LyondellBasell policy documents to require that procedures are developed for properly removing actuating equipment from plug valves,

2021-05-I-TX-2 LyondellBasell La Porte Complex - Update LyondellBasell policy documents to require that LyondellBasell competent employee(s) verify that contractors are competent, adequately trained, and qualified to perform the required work,

2021-05-I-TX-3 Turn 2 Specialty Companies - Update Turn2 policy documents to require that Turn2 employees are provided with written, detailed procedures for safely conducting work on process equipment and are trained on the procedures before the work is authorized to be performed,

2021-05-I-TX-4 American Society of Mechanical Engineers – Revise ASME Standard B16.34 Valves—Flanged, Threaded, and Welding End,

2021-05-I-TX-5 American Petroleum Institute - Revise API Standard 599 Metal Plug Valves—Flanged, Threaded, and Welding Ends, and

2021-05-I-TX-6 Valve Manufactures Association of America - Work with ASME and API and develop a white paper to the Valve Manufacturers Association of America addressing the issue of plug valve design.