[cnn-photo-caption image=http://i.cdn.turner.com/cnn/2010/US/07/15/oil.spill.faq/story.jpg caption="The Gulf of Mexico oil disaster began April 20 after the Deepwater Horizon oil rig exploded. ." width=300 height=169]
The "integrity test" on the BP well in the Gulf will continue for another 24 hours, as company and government officials determine whether the new cap is holding up.
The testing began last Thursday and was originally expected to last 48 hours. It has now been more than four days.
A federal science team and BP officials are trying to determine what's causing lower than hoped for pressure readings. The pressure readings of 6,800 pounds per square inch are lower than the 7,500 pounds engineers expected when the test began.
Scientists are also investigating possible methane gas leaks found around the well and from the broken blowout preventer, as well as from a potentially unrelated seep from the ocean floor about two miles away, former Coast Guard Adm. Thad Allen told reporters at today's afternoon news conference. But he says right now there's no reason to worry.
"It is the collective opinion of the folks that are talking about this that the small seepages we are finding right now do not present, at least at this point, any indication that there is a threat to the well bore," Allen said.
Officials believe the leaks could be occurring naturally.
Tonight on 360°, CNN's Chad Myers will explain how these natural leaks happen each day in the Gulf. He reports 40 million gallons of oil naturally seeps into the Gulf each year. 40 million gallons.
You'll also hear from Rep. Ed Markey, D-Massachusetts, who has sent a letter to Adm. Allen on Sunday seeking more information on the well testing.
"By shutting in this well, we could be shutting off our last best chance to determine what BP could pay in government fines," said Rep. Markey.
With the well shut and no oil be collected on ships on the surface there can be no analysis of the flow rate.
Markey wants to know the flow rate because he says BP will face a fine from the federal government for every barrel of oil spilled per day, up to $4,300 per barrel in the case of gross negligence.
We'll also take you back to the night the disaster began. Three months ago tomorrow, the rig burst into flames. In a 360° exclusive, you'll hear from three of the first-responders. For these three men a fishing trip turned into a nightmare.
See you at 10 p.m. ET.
Anderson Cooper goes beyond the headlines to tell stories from many points of view, so you can make up your own mind about the news. Tune in weeknights at 8 and 10 ET on CNN.
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