Fortunately, scientists have invented something called the blowout preventer, a device that stops gushers from sprouting oil. Essentially, it consists of a mechanism that stops the uncontrollable flow of oil through a well by severing the pipe with hydraulic locks. However, these blowout preventers are not always a success. The recent Deepwater Horizon oil spill was caused by the failure of the blowout preventer. Therefore, I believe that we should have multiple lines of defense. Nearly all blowout preventer has only one stopper. Having numerous stoppers will ensure that, even though the first stopper fails, the secondary and tertiary stoppers will stop the oil. By Y.J. Kim
Please refer to : http://green.blogs.nytimes.com/2010/06/21/the-era-of-the-oil-gusher/?scp=1&sq=gusher&st=cse

