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ication process called hyrotreating. [7] The unfinished products from conversion are then contacted with hydrocarbon under heat and high pressure in result to produce hydrogen sulphide and desulphurised product. The main purpose of this process is to remove sulphur in order to produce high quality products and meeting environmental standards. [6]

From the observation, every oil refinery processes from all oil production company are almost the same. But some of the company might develop different and new technology to improve their processes as they want to improve their production yield at lower cost and time.

The accidental oil spills in the ocean have occurred around the world. Previous cases, we can see that most of the oil spill happened, 90% is because of human error. For examples, BP Deepwater Horizon oil spill in Gulf of Mexico. [8]

In this case, Exxon Valdez oil spill disaster also happened in the similar causes. This case can analysis through the fish bone diagram shown below.

Fatigue is primary root cause for this accident. According to the investigation, the Third mate who was solely responsible for the navigation watch plotted the ship’s position incorrectly, possibly due to fatigue and excessive workload. This is because, he had worked for long hours before the grounding and only have 5 or 6 hours of sleep in the previous 24 hours. He was working beyond his normal watch period and with without any assistance at that time, even though Exxon company policy requires two ships’s officers on the bridge during transit of the Valdez Narrow. The research has shown that “fatigue degrades human performance and can contribute to cause error.”[9]

The second human error is people impair with alcohol. For the Exxon Valdez incident, at the time of grounding, the master was not at the bridge, so his drinking did not directly cause the accident. But, the fact he was drunk which was against the company regulation. [10] The bloods test shown that the blood alcohol content of master as high than the limit Coast Guard regulation permits to operate a ship. [11]

Moreover, the number of crew of Exxon Valdez had been cut to half from 40 people. Therefore, there were caused to insufficient crewmembers to lookout the task or sharing the workload when one of the crewmembers was called for other tasks or took a break. Those of the crews have to routinely worked 12-14 hour shift, plus extensive overtime. It caused they may not have enough rested.

At the first, according to National Transportation Safety Board, the U.S. Coast Guard had failed to provide an effective vessel traffic system. There was found that the Vessel Traffic Service (VTS) unable to track Exxon Valdez even though it has been 7.7 miles farther from the shipping lane and VTC watchstander unable to recognize the unsafe situation existed. Furthermore, they failed to provide effective supervision as they have cut down man power during the previous year. [12]

Lastly, effective pilot and escort services were lacking. There was only one tug to accompany Exxon Valdez for the passage through Valdez Narrow. [12]

The major caused of this oil spill disaster seen to be human-caused more than others factors. Risks which is lead 本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。