Over the weekend, a controversy raged over the chemical dispersants BP has used to break up the massive Gulf of Mexico oil spill. On Saturday, Rep. Edward Markey, D-Mass., released a letter charging that: “BP often carpet bombed the ocean with these chemicals and the Coast Guard allowed them to do it.” This was allowed, Markey said, despite restrictions imposed by the US Environmental Protection Agency (EPA) on the use of the chemicals.

In May, the EPA and the Coast Guard ordered BP on to cut the use of chemical dispersants by 75 percent. But according to Markey’s letter, the Coast Guard approved 74 waivers over a 48-day period after the EPA order.

As we’ve reported previously, long-term exposure to dispersants can cause central nervous system problems or damage blood, kidneys or livers. And while the chemicals do a good job of breaking up the oil into tiny droplets, scientists say this makes it easier for the oil and chemicals to be absorbed by much marine life, especially eggs and larvae.

According to the Associated Press, in response to Markey’s letter, Allen said the Coast Guard did not ignore the EPA directives, but that some field commanders had authority to allow more dispersants to be used on a case-by-case basis.

In a statement released over the weekend, the EPA said BP reduced the use of chemical dispersants by 72 percent through mid-July, when the containment cap was placed on the well

“While EPA may not have concurred with every individual waiver granted by the federal on-scene coordinator, the agency believes dispersant use has been an essential tool in mitigating this spill’s impact,” the agency said.

Meanwhile, the oil spill might finally be nearing its end. Crews are beginning preliminary testing today, and if all goes as planned, engineers will begin a process known as a “static kill” that could shut in the gushing well once and for all.

The static kill involves firing mud and possibly cement into the blowout preventer that sits on the wellhead. BP says it will take up to two days to complete the static kill. BP will continue to work on a relief well, and whether the static kill works or not, the relief well should meet up with BP’s well sometime before mid-August. Then, cement will be poured into the stricken well via the relief well.

The well has been spewing oil since the April 20 explosion aboard the Deepwater Horizon oil rig killed 11 men. The new operation comes 18 days after BP finally was able to shut off the well with a tight-fitting cap that siphons the oil to waiting surface ships.

Of course, even if the oil well is permanently shut off, the Gulf Coast still faces months or even years of cleanup. According to The Washington Post, some Louisiana officials are concerned that the government and BP will bail out prematurely in their response to the spill.

The 1,500 or so commercial fisherman employed by the “Vessels of Opportunity” program to clean up the spill could face unemployment after the well is plugged. Retired Coast Guard Adm. Thad Allen, who has been overseeing the federal response to the spill, has said there will be a “resource leveling,” once the well is fully capped. According to the Post, Allen said the government has put together a plan to keep the fishermen employed at least through August.