Brussels - European Union regulators Wednesday imposed a 173-million-euro (259-million-dollar) fine on two cartels formed by plastic additives companies whose products are used in a range of goods ranging from credit cards to bottles.

A total of 24 companies were found guilty of damaging consumers by fixing prices, sharing customers, allocating markets and exchanging sensitive commercial information at various times between 1987 and 2000.

An investigation by the European Commission in Brussels found that the participants in the cartel had met regularly and secretly in Zurich.

"The companies' elaborate precautions to cover their tracks did not prevent the (European) Commission from revealing the full extent of their determined efforts to rip off their customers," said EU Competition Commissioner Neelie Kroes.

The biggest single fine, 61.32 million euros, was imposed on Swiss company Ciba. Arkema of France received two fines, of 10 million euros and 18 million euros, for participating in both a tin stabilizer and an ESBO/esters cartel.

Chemtura Corporation of the United States also participated in the cartel but was not fined because it revealed its existence to the commission. (dpa)