H2S gas affects sea man

An accident happened on loading the cargo in chemical tanker.The crude had to load CST (crude sulphate turpentine),2000 tonnes. The MARPOL annex II gives a category X to the CST.
       The crew members were explained  onboard before loading but not perfectly or exactly with this type of cargo,they strictly fallowed all procedures and check list, including P&A and SMS of the tanker.

     The chief officer gave prior instruction  and arrival but the MSDS were missing and the cargo hazards were not explained properly. 
The crew received only generic MSDS but the

 toxicity of hydrogen sulphide (H2S), organo-sulphides and 

mercaptans were not mentioned.


Due to that,only a respirator filter was used by the surveyor

. This was not effective against the vapours from the H2S.

 The Butterworth hatch of the tank was opened by a seaman

 who did not even wear a respirator.

The situation was seen by another crew member. He

 informed the chief officer and then the Master. He sound 

the general alarm on the vessel bridge. At that time, the

 chief officer tried to save the seaman but he was not 

wearing any apparatus, neither was prepared for the 

atmosphere. When he approached, he became 

unconscious. An attempt to rescue the seaman and the chief

 officer was done by another crew member. He held his 

breath but still the vapours affected him badly.

Finally, the seaman and the chief officer were rescued by

 other crew members who were wearing breathing 

apparatus. At the hospital, where they were taken, they were

recovered completely.

The root cause of the accident were found:

1.Insufficient MSDSs version;

2.Inappropriate briefing prior arrival;

3.The strong odor was ignored and breathing apparatus

 were not in use;

4.The fixed washing system was defective;

5.Lack of identification of potential danger, for instance - the 

place of the Butterworth hatch;

6.The initial rescue attempt was an act of impulse, the chief

 officer did not use breathing apparatus, neither the

 atmosphere was checked

.
7.The Master did not follow terminal emergency procedures.