Four siblings who are directors of a company have been fined €10,000 after being found guilty of storing and using diesel with sulphur levels far higher than the legally-established limit.

Brothers Gaetano, Manweli, Joseph and Carmelo Abdilla, directors of Ramel u Żrar Limited of Dingli Cliffs, were accused of failing to exercise due diligence in the use of fuel which did not conform to specifications.

The case took place in March 2012, when Malta Resources Authority inspectors took samples of diesel stored at the company’s premises.

According to the Quality of Fuels Regulations, only diesel fuel with a sulphur content of up to 10mg/kg could be used. But tests carried out by Saybolt showed a far higher concentration of sulphur in Ramel u Żrar's fuel, with an average of 389mg/kg.

The eldest brother, Gaetano, testified that the company never purchased contraband diesel, stating that he always bought diesel from two companies - Falzon Service Station and Cassar Petroleum Services Ltd.

He provided receipts showing regular purchases of fuel but was not in a position to say which company had supplied the diesel tested.

Magistrate Consuelo Scerri Herrera said that the issue was not whether the brothers knew that their company’s diesel was not up to spec, but whether they actually used it.

The simple use of off-spec fuel was already considered a crime, she ruled as she imposed the fine.