Oil is a precious commodity and it is very expensive. It is believed that the worlds oil reserves will run out within the next 40-50 years. Oil is so valuable that is was the main reason why the Gulf War began. As it is so expensive underdeveloped countries can sometimes not afford it even though they desperately need it for transport, which stops their countries growth. So as you can image if one of these ships started to leak it would have a serious detrimental effect on the environment.
Oil spills can cover a massive area.
It took a long time for this region to recover. To prevent oil spills, I feel oil companies must be so accurate that every part of the tanker is leak proof. There should also have a clean up crew ready if there is a oil spill. When oil and coal is burnt they emit huge amounts of carbon dioxide and other harmful gases, that have a negative effect on the environment, like sulfur dioxide. If temperatures are too hot it is terrible for children and elderly people who find it hard to cope with hot conditions.