Hazardous and Noxious Substances Spill Incidents

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On this database it is collected information on the fate and weathering of hazardous and noxious substances (HNS) accidentally spilt at the sea around the world. It gathers and systematizes existing information to assist stakeholders involved in spill preparedness and response, and builds return of experience datasheets for the chemicals involved. It will facilitate the incorporation of lessons from past incidents on the decision process to improve preparedness.

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The Netherlands



HNS Spilt



Amount Spilt (T)51

CAS Number7782-50-5


Physical Behaviour (SEBC code)


Pollution Category (MARPOL Annex 2)


Class according to IMDG code


Subsidiary Risk Class according to IMDG code

Classification as Marine Pollutant


HNS Classification (2010 HNS Convention)

Fate and weathering facts observed/reported

Location by side-scan sonars and by a remotely operated vehicle (ROV) of 7 cylinders. Recovery of 5 other cylinders by fishermen. Search 5 years later for other cylinders: 27 found and destroyed. Thirteen cylinders still missing. Some of the found cylinders were moored to a safer place on the seafloor. Divers then placed explosives under each cylinder, which was then blasted in controlled conditions. The chlorine rose to the surface and, in one hour, a cloud developed, stretching 300 m wide, 3,000 m long and 300 m high. It was made more clearly visible by releasing ammonia from a ship upwind. The reaction between ammonia and chlorine formed a clearly visible white cloud of ammonium chloride. Single seabirds were occasionally observed flying into the gas cloud and falling immediately like stones to the water surface but no serious ecological damage was detected from chlorine. Chlorine is toxic, harmful to human health (through inhalation) and reactive, producing a corrosive acid when mixed in water.

Material Safety Data Sheets (MSDS)