BRUSSELS (AP) -- EU regulators on Wednesday jointly fined Akzo, Ciba, Elf Aquitaine and seven others euro173 million (U.S. $260 million) for fixing the price of plastic additives.

Ciba was fined euro68.4 million, Akzo was ordered to pay euro40.6 million, Elementis must pay euro32.57 million and Elf Aquitaine euro28.6 million. Baerlocher, Reagens, GEA and Faci were fined smaller amounts. Chemtura escaped a fine for alerting the EU executive to the cartel.

The European Commission said the companies fixed prices, shared customers, carved up markets and swapped commercial information from 1987 to 2000 for tin stabilizers and ESBO/esters heat stabilizers, two additives used in packaging, credit cards, bottles and other plastic products.

The market for the stabilizers was worth some euro121 million a year during the time the cartel was active, the EU said.

Tin stabilizers are used to protect PVC plastic from heat when it is being formed into final products. Heat stabilizers are added to PVC products to help them cope better with higher temperatures, make them more rigid and protect them from discoloration.

EU Competition Commissioner Neelie Kroes said "these companies must learn the hard way that breaking the law does not pay and that repeat offenders will face stiffer penalties."

Regulators said they had increased a fine on Arkema France -- owned by Elf Aquitaine -- by 90 percent because it has been found guilty of joining three other cartels before. However, it also granted a small reduction to Arkema, Baerlocher and Ciba for sharing information with officials.

Swiss consultancy AC Treuhand was also fined euro348,000 for aiding the cartel and hosting monthly meetings at its Zurich offices -- held outside the European Union in an effort to evade EU antitrust officials who can seize documents from offices within the EU.

Kroes said the companies' "elaborate precautions to cover their tracks did not prevent the Commission from revealing the full extent of their determined efforts to rip off their customers."