A well-known oil and coal company has been fined for a pollution incident at Belfast Harbour.
Hayes Fuels, which has its headquarters in Tyrone, was taken to court after an investigation by the DoE.
A routine inspection last year found that "highly polluting" material was running into Belfast Harbour from a coal yard owned by the firm.
A fine of £500 was imposed at Belfast Magistrates Court yesterday and the business was also ordered to pay costs totalling £272.62.
It was prosecuted for a similar offence in 2004, the DoE said.
In a press release on the case, the Department also stated: "The incident was discovered on September 21 2006, following a routine inspection by an officer from Environment and Heritage Service (EHS) of a coal yard at Dufferin Road, Belfast, belonging to Hayes Fuels.
"It was found that run-off, which was badly contaminated by coal dust and solids, was escaping from the coal yard and entering Belfast Harbour. Analysis confirmed that the discharge was highly polluting."
The DoE said Hayes Fuels had pleaded guilty in court yesterday and stated that remedial work had been carried out to ensure that such an incident would not happen again.
Hayes Fuels describes itself as one of Ireland's leading coal and oil distributors.