Yang explains reasons for hamster study
Dr. Julie Yang said that during her time as a chemist at W.R. Grace, she was moved to request the so-called “Hamster study” after learning about tremolite asbestos from numerous scientific journals, colleagues and her own testing.
Judge Donald Molloy kicked off the post-lunch proceedings by stating that he would allow the much-contested government exhibit 144A. The judge noted however that Yang could not testify to the first sentence referring to “super clean” vermiculite, the source of defense attorney David Bernick’s objections to the exhibit. Molloy also instructed the witness to speak loudly, a request heard many times throughout the afternoon.
“You have microscopes, we have microphones,” he said.
Leaning into the microphone, Yang said that in her time at the company, she tried to reduce the levels of tremolite releases through a variety of methods with limited success. Using water or other bonding agents to coat the outside of the ore was seen as a possible solution to high worker exposure, but Yang said her testing revealed the limits of this practice.
“If you bind the fine particles, at least the dust levels will be down,” she said, noting that the improvement was only temporary. “Once it dries up, it won’t work.”
After consulting “hundreds” of scientific journals on tremolite and speaking with Dr. William Smith and others, Yang said that she recognized the hazards of asbestos and became interested in pursuing a more in depth analysis of the Libby ore. Yang said that the testing she oversaw was presented to her boss at Grace, and she helped write the request for the hamster study. All of her testing was compiled into a report showing different percentages of tremolite in Libby ore and the viability of removing it.
“This is a sort of summary putting all of the data into one place,” she said of the report, admitted as government exhibit 369.
After receiving approval for the study, carried out by Smith, Yang testified that she prepared samples from the Libby mine for injection into the animals. During cross examination, defense attorney Krakoff established that Yang worked to replicate the same fiber composition that was found on filters worn by Grace employees in the mine. Krakoff made it clear that the methods used in the experiment, injection into the pleural cavity, was vastly different from the way that humans contact asbestos. Molloy asked Krakoff to hold further questions until later, calling for an afternoon recess at 3:00.
–Kyle Lehman (posted 4:25)