US EPA

2842013 

Journal Article 

Violent explosion after inadvertent mixing of nitric acid and isopropanol - Review 15 years later finds basic accident data corrupted, no evidence of broad learning 

Hedlund, FH; Nielsen, MF; Mikkelsen, SH; Kragh, EvaK 

2014 

1 

Safety Science
ISSN: 0925-7535 

70 

255-261 

10.1016/j.ssci.2014.06.010 

WOS:000343361400027 

At a brewery in 1997, an operator confused filling nozzles for two commonly used acid cleaning agents and transferred nitric acid into a tank with P3, a proprietary phosphoric acid based cleaner that also contained 5-15% isopropanol. 10-15 min later the mixture exploded violently. The stainless steel tank disintegrated with such force that fragments lodged in walls of concrete. The explosion ravaged the cellar, destroyed equipment, blew out a masonry wall and released large amounts of nitrous oxide fumes. Likely, 62% nitric acid (CAS 7697-37-2) and isopropanol (2-propanol, CAS 67-63-0) reacted to produce isopropyl nitrate (nitric acid 1-methylethyl ester, CAS 1712-64-7), a rocket propellant. It is argued that the accident has broad learning potential because of the widespread usage of the two chemicals across industries, the innocent nature of the human error and the severity of the consequence.



A review 15 years later of lessons learned finds that information dissemination has followed a tradition of informal meetings in small industry sector associations but impact is unclear. There is no useful mention of the accident in open sources. Although the Danish Working Environment Authority took the brewery to court for negligence, they did not report or investigate the accident, or attempt to disseminate information available to them. Today, the general literature is silent on the explosion hazards of mixing the two chemicals.



The paper argues that without institutional support, learning opportunities are missed and broader cross-sector learning is limited or non-existent. (C) 2014 Elsevier Ltd. All rights reserved. 

Clean-in-place (CIP); Nitric acid; Chemical incompatibility; Explosion; Learning from past accidents