200758 - Ballast tank explosion fatality

Ballast tank explosion fatality	MARS Report 200758

Source: IMO Sub-committee on Flag State Implementation at its 12th session
 

While at anchor, the crew was engaged in cleaning and painting the topside ballast tank as part of an ongoing maintenance programme. The tank had been opened some days before; the mate tested the tank for oxygen level a few times and found it to be 21 per cent. After approximately two hours of painting, using a spray gun to apply epoxy paint with thinners, there was an explosion which blew the tank apart. Five crew members died and three were missing.

Root cause/contributory factors

1. The epoxy paint contained more than 30 per cent thinners. Spray painting using such a mixture can create vapour concentrations within the explosive range of the mixtureÅfs compounds;
2. The tank was ventilated using a fan blowing air through a manhole and a compressed air line situated in the tank, which was inadequate;
3. A cargo light was used to illuminate the work area, which was not intrinsically safe/explosion proof.

Lessons learnt

1. The crew needs to appreciate the potential possibility of an explosion when spray painting.
2. The safety management system should set out procedures for painting in enclosed spaces.
3. Material safety data sheets which provide flash points, explosive limits and ignition points for the paint base, hardener and thinner should be understood by crew on board.

Editor's note: It is unsafe to introduce a compressed air hose into any space that may, even remotely, have a flammable air and gas or air and vapour mixture. These are difficult to earth electrically and the release of compressed air from its open end has a high potential to generate an electrical spark.