UK accident investigators have warned of the dangers of hydrogen gas being released from ash cargoes after a double explosion injured an engineer on a German general cargoship.

The 2,600-dwt Nortrader (built 2012) was rocked by two blasts off Plymouth on 13 January this year, putting it out of action with extensive damage for more than three months.

The chief engineer was out of work for four months after suffering second-degree burns.