At least 900 refrigerated containers (‘reefers’) have been identified and quarantined at locations around the world after a series of mysterious explosions, according to the World Cargo News.

While the precise causes of the explosions are still under investigation, Maersk said it had ascertained that all three refrigeration units involved had received gas repairs in Vietnam between late March and late April. It is suspected that a contaminated or incorrect refrigerant was introduced to the system that creates a flammable or explosive mixture after combining with air, oils, or other chemicals present.

Owing to this uncertainty, all makes of reefer and all carriers could presently be affected. Carrier Transicold, the world’s biggest reefer container machinery manufacturer, sent an urgent safety bulletin to service centres: customers are advised to quarantine any units that were serviced in Vietnam in 2011 and not to attempt top service such units as serious injury or death could result from apparently spontaneous combustion.