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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Brigitta Montanari





HNS Spilt

Vinyl Chloride monomerGas


Amount Spilt (T)600

CAS Number75-01-4


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

Vinyl Chloride Monomer (VCM) is normally transported as a compressed liquefied gas. When spilled in the water, 10 to 20% of liquefied VCM evaporates instantaneously. The rest of it floats , and forms a slick that will spread and evaporate. Vinyl vapours are heavier than air and tend to hug the water surface. Some of it will solubilise and accumulate slightly in aquatic organisms. Ship sank in waters 82 m deep in the Adriatic Sea. The wreck was brought up to a depth of 55 m to be towed underwater to a small sheltered bay where it was grounded. Part of the cargo was then pumped to the surface and transferred onto another vessel. A daily leakage of 3 T a day was estimated when wholes were drilled for pumping. A concentration of VCM in the water column 300 m from the wretch was more than 5 ug/L. At the surface, VCM was either left to disperse in the atmosphere or was burned. In 1987 biological monitoring was initiated in some communities. The wreck was covered with marine organisms despite VCM concentrations were often seen to bee relatively high (>10 mg/L). In the light of the results it seem that sublethal effects may have occurred on sedentary benthic fish population, but these results were never confirmed.

Material Safety Data Sheets (MSDS)