The dredger 'Sand Falcon' discharging dredged material off Sunderland.

The ship had been dredging the main shipping channel in the River Tees east of Middlesbrough. There had been considerable controversy about this as there has been a significant die-off of marine life that closely matched the dates of the dredging. As one of the most polluted areas in Britain, there was suspicion that the dredging may have disturbed various harmful substances but despite independent environmental testing, the culprit of the marine deaths has not been identified.