Vass, a forensics expert, has pioneered a technique for detecting human decomposition from air samples. Prosecutors intend to use this technique to prove that Anthony suffocated her daughter with duct tape in 2008.
Dr. Vass said other researchers at ORNL helped with his testing. He asked the sheriff's office to take hair samples from various parts of Anthony's car and the garage. He sent investigators equipment to use.
He said they collected samples of the air in activated carbon and took it back to a lab for analysis.
Vass said many of the chemicals found in decomposition were found in the trunk of Casey's car.
When he first opened the can with the carpet sample, Dr. Vass said, "I essentially jumped back a foot or two. The odor was extremely, overwhelmingly strong, and I was shocked that that little bitty can could have that much odor." He said he identified the smell as human decomposition.
Although he has sampled road kill in the past, Vass said the odor of human decomposition is different and unique.
Vass said chloroform is a decompositional component and a large peak in the analysis of that carpet sample was chloroform.
The sample was "shockingly high," Dr. Vass told the jury. "We have never seen chloroform in that level in environmental samples or at least I never have in 20 years of shooting these types of samples."
Laser tests for inorganic compounds in the carpet sample showed high levels of calcium, magnesium, sodium and iron, among other substances.
Vass said other peaks in the tests showed components of gasoline.
Lead defense attorney Jose Baez made several objections to Vass' testimony throughout the morning, attacking both his credentials and methodology used in doing his research.
He briefly was permitted to question Vass' methodology outside the presence of the jury, but was stopped after Judge Belvin Perry said the questions he was asking him were outside the scope of his original objection. His objection was then overruled and the jury was brought back in.
Perry previously issued a pretrial order denying a defense request to exclude the air tests from the carpet sample taken from Anthony's car. Tests for odors associated with a body's decomposition were run on the carpet sample and the tests identified chloroform in the sample.
Until now, the tests had never been admitted in a trial in the U.S.
Casey Anthony has pleaded not guilty. Her defense says Caylee drowned in her grandparents' swimming pool.
If convicted, Anthony, 25, could be sentenced to death.
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