Illegal Tank Entry

Illegal Tank Entry
Report No. 200326

Anyone with experience from ships in general and from tankers in particular can testify about the dangers of entering an enclosed space. The following incident happened a few years ago onboard a 45,000 dwt. chemical tanker. The vessel was normally trading with clean petroleum products in the US Gulf. Tank cleaning, when needed, was usually a simple operation of giving a quick wash with fixed tank cleaning machines using sea water and fresh water. The tanks remained inerted and the residue water, after stripping, was ejected by lowering a Golar-ejector into the tanks via a hatch adjacent to a pump. Thus, an entry into the tank was not necessary for making the tank dry before tank inspection. Occasionally, the ship got to load chemicals for Europe, in these instances an extensive tank cleaning was carried out, mainly to remove the inert gas soot that had been building up on the bulkheads. The tanks were washed, made gas free and, after enclosed space entry permits had been issued, the crew could enter for mopping.

On this particular voyage the pre-loading tank cleaning, loading and loaded passage went without problems. The discharging in the European port was also problem-free but when we left the port and started tank cleaning the incident this report is about happened.

In European waters with short distances between load ports, tank cleaning is always a rather stressful operation in order to get the tanks ready for next cargo. As soon as we left port, the tank cleaning commenced and went according to plan. The tank (5 CT) where the incident was about to take place had, after the discharge of liquid caustic soda, been washed with fixed machines for three hours. The tank was only to be ejected dry from tank washing water. Since the ship also was equipped with a nitrogen gas plant, it was practice to use nitrogen as much as possible for inerting in order to avoid soot generated from the inert gas plant entering the tanks. The next cargo was petroleum, so as soon as the tank washing was completed the nitrogen inerting commenced.

At this time, around midnight, both the Bosun, (there was no Pumpman onboard) and I had worked long hours and went for a rest. Before I went to bed I gave the Bosun a written instruction about which tanks to eject and to close the nitrogen supply to 5CT and open it to another tank. An experienced AB was given the instruction and put in charge on deck. He, with the help of two OS, started to eject the tanks from the top. Nobody was supposed to, or had been permitted to, enter any tank.
After a few hours in bed I was woken by the general alarm and rushed to the muster station. During the mustering a crew member told me that an OS was inside a tank (5-CT). Immediately two AB's got into BA sets and entered the tank. Meanwhile a davit was rigged by the tank entrance hatch and a rescue stretcher was lowered down. Due to the rapid reaction of the crew, the OS was, within minutes, out of the tank and given oxygen. He was never unconscious but when he got down in the tank he couldn't move his legs and arms. I later measured the oxygen in the tank to be 14%. In the next port, the OS visited a doctor and was declared to be completely fit.

It transpired that, when he was ejecting 5CT, the OS who entered the tank had dropped a glove through the open hatch. He had discussed with the AB about going down and the AB had told him to contact the 00W on the bridge. The OS didn't follow this advice and with the other OS standing by the tank entrance, he went down in the tank to recover the glove. Since there is no gas from caustic soda and nitrogen looks and smells like air, he thought it was safe to enter. However, as a precaution he put on a gas filter mask. Luckily, the OS standing by the tank entrance did not attempt a rescue by himself, instead he acted properly and informed the bridge.

At a subsequent safety meeting to discuss the incident, it was agreed that, since the ship always used the proper procedure for enclosed space entry, the OS should have known not to enter any tank without a permit. However, we discussed how to improve safety by using different warning signs such as "TANK INERTED" and "DO NOT ENTER". It was decided that the cargo tanks hatches at all times, except when an entry permit had been issued, should be wired and padlocked.