Alessandro Primo

On the 1st February 1991, the chemical tanker the Alessandro Primo was en route from Gela (Sicily) to Ravenna (Italy) when she sank in the Adriatic Sea, some 30 km from Molfetta (Italy) with her cargo of 3,013 tonnes of 1,2-dichloroethane and 549 tonnes of acrylonitrile. The wreck sank in waters 108 m deep. The 14 crew members were evacuated by a lifeboat.

An emergency situation was declared and a technical advisory committee set up. An exclusion zone was established within a radius of 10 nautical miles around the wreck, where navigation and fishing were prohibited.
The vessel was lying on her starboard side. The first pictures of the wreck showed a rupture in an acrylonitrile pipe. This leak was sealed using epoxy resin. The owners were requested to remove the wreck to prevent any possible pollution.
  

The acrylonitrile and the 1,2-dichloroethane were in sealed containers. Acrylonitrile is a highly flammable liquid, used to make synthetic rubber and nylon for instance. In seawater, acrylonitrile dissolves and evaporates. 1,2-dichloroethane is a colourless, flammable, toxic liquid, used as an intermediary in the production of paints, varnishes and various plastics. Upon contact with seawater, it dissolves.

After two months of in-depth study of the wreck and her tanks, a recovery plan was put into action. Pumps (40 - 60 m³/h) were sent down to the seabed, and the tanks were connected to the pumps using deck cargo lines. The pumping operations lasted a week. A fleet was made available at the surface by SMIT TAK, including a diving support vessel, recovery vessels (one for each product) and a lifeboat (and infirmary) for 50 people with a helideck. Nearly three months after the disaster, 2,733 tonnes of 1,2-dichloroethane had been recovered from the wreck's tanks, in addition to 2,850 m³ of water-dichloroethane solution and 900 m³ of acrylonitrile mixed with water.