This was confirmed by Croatian Environment and Nature Protection Minister Mihael Zmajlovic during his visit to Slavonski Brod, about 200 kilometres east of Zagreb, on Saturday evening. He said that last week he had requested an urgent response from the refinery's management board after excessive emissions of hydrogen sulphide were recorded in Slavonski Brod, which is situated across the Sava river from Bosanski Brod, even though regular repair and maintenance work on the refinery should have begun on November 11.

"It turned out that partial overhaul began on November 11 and that now the refinery is under full repair. The smoke that is seen coming from the chimney is water steam, that's what they say," Zmajlovic said. "We are exerting pressure on the Bosnian authorities to force the Bosanski Novi refinery to continue and complete its modernisation so that the problem of air pollution is solved to everyone's satisfaction as soon as possible," he added.

The refinery resumed production three and a half years ago after it was bought by Russian owners. EUR 120 million has been invested in its modernisation to date and a total of EUR 750 million will have been invested by the end of 2015 when the modernisation process is to be completed. One of the goals of the modernisation is to reduce the emission of harmful gases to the minimum, sources at the refinery have said.

Ever since the refinery resumed operation, residents of Slavonski Brod have been complaining about air pollution. A measuring station that was installed two years ago regularly records excessive levels of hydrogen sulphide and occasionally of benzene.

Regular repairs of the refinery's plants will alleviate the problem but only until the new year when the refinery is due to continue operating, so the authorities in Slavonski Brod are seeking faster and more effective ways of tackling this environmental problem between the two countries.