国际英语新闻：Gulf oil spill hits 100 days as BP struggles for fresh start

There are of course piles of private lawsuits and a probe by Texas authorities into possible excessive pollution in April and May at a BP refinery in Texas City, which suffered a deadly explosion in 2005 that killed 15 and injured 180.

Though the well has been finally plugged and the visible effects of the oil spill have largely disappeared, scientists are still assessing the long-term environmental damage.

An argument is already brewing over the long-term impact, with some scientists warning that the whole biological network in the Gulf of Mexico could be changed by the spill and others saying the effect could be quite small.

Some scientists cautioned that a large amount of runaway oil is still in the Gulf but its quantity and whereabouts remain unknown. They feared that much of the oil had been trapped below the surface following the use of millions of liters of chemical dispersant. Evidence has been found that large clouds of oil suspend in the water.

As this oil can affect the food chain and deplete oxygen in the water, scientists say that they want to know how fast the oil is being eaten by microbes and being diluted and where it is heading for.