Accidental acid spills

There have been numerous accidental spills involving acid at sea and in ports, due to collision, grounding or equipment failure. The consequences have in certain cases been dramatic for the crew. They have always been highly localised, temporary and of minor impact for the environment.

Phosphoric acid spills in the aquatic environment include:

• The presence of barrels of phosphoric acid in the diverse chemical cargo of the Cason, which grounded on 5 December 1987 on the Spanish Cap Finisterre and went on fire (see the Cason archive)
• A 336 tonne leak of a solution of fertilisers made up of 75 % phosphoric acid into a river, from a fertiliser factory in Gibson, Florida, USA on the 4 May 1988
• The derailing of a train near Bethel (North Carolina, USA) carrying chemicals, including phosphoric acid, with a partial spill in a tributary to the river Tar on 1st February 2000.
• The spill into a sewage network feeding into the river Peace of 15,000 m³ of industrial water containing phosphoric acid, by a fertiliser manufacturer in Lakeland, Florida on 29 September 2004 due to a hurricane.

The impact studies that were carried out did not reveal any significant environmental effects from these accidents directly linked to the phosphoric acid apart from at the actually spill point.

Several sulphuric acidspills have been known to occur, in particular:

• A maneuvering error leading to acid been pumped over board for 11 days, in the Trevo terminal, Brazil in August 1998 (see the Bahamas archive)
• 100 tonnes of concentrated sulphuric acid being found in the compartments of the double hull of the Panam Perla on 10 November 1998 (see the Panam Perla archive)
• The low profile shipwreck of the chemical tanker the Balu off the coast of the Bay of Biscay on 20 March 2001 with 8,000 tonnes of sulphuric acid onboard (see the Balu archive)
• The shipwreck of the chemical tanker Ena 2 in the port of Hamburg on 28 June 2004, due to a maneuvering error, with 6 tonnes of sulphuric acid in a dock (see the Ena 2 archive)
• The rupture of part of a 11,000 tonne tank at Kemira chemical plant in Sweden, on 4 February 2005, led to a toxic cloud being produced and an exothermic reaction with the water. For 3 hours 110,000 inhabitants were not allowed to go outdoors while the toxic cloud dispersed.

As for chlorhydric acid:

• In the Netherlands in 1979, the Sinbad lost 51 one-tonne cylinders of chlorine, which when it reacts with water produces chlorhydric acid. A number of cylinders were quickly located and recovered. Five years later, 27 cylinders had been recovered and destroyed on the spot because of corrosion. 13 of the cylinders were never found.
• On 28 April 1998, the chemical tanker Martina, loaded with 600 tonnes of chlorhydric acid, collided with a container ship in Swedish waters. The ship broke in two and sank. Five members of the crew went missing. The cargo was unloaded.

In terms of nitric acid:

• On 7 May 2000, off the coast of Alexandria in Egypt, the Dalhia-S was wrecked with 165 tonnes of nitiric acid onboard. Intervention on the wreck was envisaged but never carried out.
• The canal boat the Stolt Rotterdam went on fire and sank on the Rhine in Germany on 15 November 2001, with 300 tonnes of nitric acid. The acid was pumped out of the tanks which remained intact, an operation which lasted a week.

 The main problem encountered in these accidents was the risk involved for the crew and, in port areas, for the inhabitants, in particular in the case of the production of toxic fumes and exothermic reactions when the acid came into contact with a metal. For this reason, the loss of human life was the tragic consequence of the Cason and the Martina disasters.
 
Information about the environmental impact of acid spills is very limited, either due to a lack of investigation (e.g. for the Balu), or because the studies were of little use, often being more qualitative than quantitative (e.g. fertiliser factory in Gibson).