Santa Clara I

On 4 January 1992, in adverse weather, the Panamanian container ship Santa Clara I lost 21 containers overboard some 30 nautical miles off the coast of Cape May (New Jersey). Four of these containers lost at sea were loaded with drums of arsenic trioxide. On the other hand, two damaged containers remained on the vessel holding this highly toxic chemical, whose lethal dose for a human being is 100 mg.
 
 A sum total of 414 drums of arsenic trioxide from containers was lost overboard in 125 feet of water. The search for the drums took place with participation of vessels, planes and helicopters. 320 drums were located and brought to the surface with two large ROVs (Remotely Operated Vehicles).
 
 When Santa Clara I arrived in the port of Baltimore the day after the accident, a container of arsenic trioxide was dangling precariously off the port side of the ship, while the main deck and several cargo hatches of the vessel were literally covered with the lethal powder. It took little more than one day to clean up everything.
 
 Later, when Santa Clara I stopped over in the port of Charleston, a grey powder was found covering the floor of the holds. Even though arsenic trioxide was the only hazardous cargo indicated in the vessel manifest, it became clear that around 400 kg of magnesium phosphide covered the floor of the hold. Because this substance could release flammable vapours when wet, the hold was closed and sealed to keep out any moisture. The ship was evacuated except for an emergency team of 10 crew members. It was then taken to a more isolated anchorage where it was decontaminated by qualified, trained and equipped personnel.

Sources :

- HELCOM, 2002, HELCOM Response Manual - Volume 2
- MAMACA Emina, GIRIN Michel, LE FLOCH Stéphane and EL ZIR Rawad, 2009, Review of chemical spills at sea and lessons learnt, Interspill conference 2009
- Cedre, 1993, Recherche d'aide à la décision concernant le choix des interventions à mener en cas de perte en mer d'un colis contenant des produits chimiques