(AP) -- Dead birds are wrapped in foil or paper, then sealed in plastic bags to avoid cross contamination. Dolphin tissue samples and dead sea turtles are kept in locked freezers. Field notebooks are collected and secured.
Scientists examining dead animals that were discovered along the Gulf Coast in the wake of the BP oil spill are observing strict laboratory protocols, knowing everything they touch could become evidence in what may prove to be the biggest environmental case in U.S. history.
Like detectives on a murder case, government scientists - and outside experts under contract to the government - are using CSI-style techniques to determine whether the oil is to blame for the wildlife deaths.
The U.S. Justice Department is investigating whether those responsible for the spill violated environmental laws that carry civil and sometimes criminal penalties, and the scientists are taking extraordinary steps to make sure their findings hold up in court.
"What we want to do is to make sure that the findings and the results we get aren't called into question in court based on chain of custody or other legal issues," said Dr. Michael Ziccardi, a veterinarian. "We're treating oiled wildlife response like a crime scene."
Justice Department spokeswoman Hannah August declined to comment on the investigation. Attorney General Eric Holder said in June that the government will prosecute violations of such laws as the Clean Water Act, the Migratory Bird Treaty Act and the Endangered Species Act.
The number of dead creatures will help determine the fines and penalties levied against BP and other companies involved.
Wildlife deaths will also figure into the government's assessment of the spill's damage to the Gulf's natural resources. That accounting could take years and will be used to bill BP and the other companies for the cost of restoring the environment.
By some estimates, they could be forced to pay billions of dollars - more, perhaps, than the penalties associated with the Exxon Valdez disaster.
Exxon was hit with a record criminal fine of $150 million for the 1989 tanker spill in Alaska but ultimately paid $125 million in penalties. It also agreed to pay $900 million to settle federal and state civil claims. The spill of nearly 11 million gallons was the largest in U.S. history until it was eclipsed by the Gulf gusher that spewed some 206 million gallons from the blown-out BP well over three months.
BP spokesman Robert Wine noted the oil company set aside $32.2 billion during the second quarter to cover the long-term cost of the spill.
Since the Deepwater Horizon rig exploded April 20, killing 11 workers and triggering the spill, authorities have found thousands of dead animals.
But animals die every year in the Gulf from a variety of factors, including fishing, hurricanes, low oxygen levels and disease. And the vast majority of the hundreds of dead dolphins and sea turtles have had no visible signs of oil, so scientists have been forced to look more deeply.
"Is there damage to the eyes, to the skin? Are there lesions in the stomach or in the lungs, which can occur during oil exposure. Is there microscopic damage to the liver, the kidney?" said Ziccardi, who directs the Oiled Wildlife Care Network at the University of California at Davis.
The results of the laboratory tests are still being compiled.
The dead animals are being kept at universities and public and private research centers across the Gulf Coast.
Carcasses are taken from the freezer, thawed, photographed and examined internally and externally. Anyone who handles one of the carcasses must sign a log sheet that is used to keep track of when remains are removed and when are they put back. The notebooks in which scientists recorded when and where they found a particular animal are regarded as vital evidence, too.
"Pretty much in this case here," said Peter Tuttle, acting Interior Department case coordinator for the natural damage process, "everything is considered evidence."
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More information: U.S. government list of Gulf wildlife collected: http://www.nmfs.noaa.gov/pr/health/oilspill.htm