Helsinki (xn) - Several tonnes of hazardous material slipped off the deck of a Finnish-owned ship into the Baltic Sea on Saturday morning, local media reported on Sunday. The accident occurred near the southern coast of the Swedish island Gotland.

The ship's owner Langh Ship Company said three containers fell overboard after one container on deck collapsed under the weight of other three others. One of the containers holds several tonnes of material used in the chemical and plastic industries.

Niklas Guseff of the maritime rescue co-ordination centre in Turku, Southern Finland, said the ship's crew contacted the center after the incident. Such accidents are rare. It could cause damage to the environment if the hazardous materials begins to leak, he added. Guseff said that the Finnish Maritime Administration is working together with Swedish authorities on the matter.

The Swedish Coastguard said the container holds inflammable material as well as other hazardous compounds. The Swedish Coastguard is planning to search the area for the container.

The Finnish-owned ship "Linda" was en route from Rotterdam to St. Petersburg when the accident occurred. The ship had been leased by the sea carrier Containerships. Mimmi Nordstrom, the deputy managing director of Containerships, said only one of the sunken containers holds hazardous material.