A chemical company experienced two major uncontrolled releases of highly corrosive acids. In January 2020, approximately 300,000 litres (8,000 gallons) of hydrochloric acid leaked from the site, releasing toxic gases that forced the closure of local businesses and schools and caused residents to evacuate their homes. A second incident in August saw 87,000 litres (23,000 gallons) of sulphuric acid escape. Fortunately, no one was injured in either incident, but the released toxic gases had the potential to cause harm to people and the environment.
Following the leaks, HSE and the Environment Agency carried out a joint investigation. An HSE specialist, mechanical engineering inspector, worked alongside the Engineering Materials Team to determine what went wrong and why the chemicals were released. Their detailed examination combined destructive and non-destructive tests with microscopy to determine the contributing factors that led to the pipework failures.
The forensic examination revealed that:
- the polymeric pipe failures resulted from improper installation, creating additional loading, coupled with a surge pressure event from incorrect operation
- the metallic pipework failure resulted from preferential corrosion – a specific degradation pattern caused by the combination of acid corrosion and high-velocity fluid flow, leading to erosion-corrosion
Crucially, both incidents were partially attributed to inadequate inspection and maintenance regimes:
– failures that could have been prevented had the required process safety standards been followed.
CLICK HERE for the images