Release and fire from a hydrogen pipeline

An in-line inspection of the hydrogen pipeline was being conducted and prior to the last run of the in-line inspection tool (magnetic flux leakage), hydrogen gas was released and ignited from a blind flange connection failure on a temporary separator filter installed at the receiver site.
The fire was immediately identified by on-site personnel. There were no injuries. The pipeline section was isolated and de-pressurised to the facility flare. Local emergency responders were dispatched and contained and extinguished the fire. The fire affected the station piping and equipment in the surrounding area. Repairs and/or replacement of affected piping and equipment were completed and re-commissioned.

Failure of a blind flange connection, which had been temporarily installed to allow for an in-line inspection.
According to the PHMSA report, there was no indication that the actions of the controller(s) or control room were the cause of, or a contributing factor to, the incident.

aboveground pipeline, blind flange connection

The incident occurred during an inline inspection.