SAN FRANCISCO (CN) --- After emotional testimony by two women whose eggs and embryos were damaged in a fertility clinic mishap, a cryogenic tank maker called its first witness Thursday to dispute claims that a manufacturing defect caused the catastrophe.
Franklin Miller, a mechanical engineering professor from the University of Wisconsin who used to work on cryogenic systems for NASA, testified that Pacific Fertility Center employees are to blame for an accident that prematurely thawed 3,500 frozen eggs and embryos at a San Francisco fertility clinic on March 4, 2018.
“I have the opinion that Pacific Fertility misused the MVE 808 when they unplugged the controller,” Miller said, referring the cryogenic tank's model number and controller device that monitors liquid nitrogen levels and sends off alerts about tank problems.
Miller was hired by tank manufacturer Chart Inc. to rebut testimony that the accident was caused by a manufacturing flaw.
The clinic’s lab director, Joseph Conaghan, testified last week that he unplugged the tank’s controller device 17 days before the equipment failure. He said the controller was malfunctioning and sending out false alerts about low liquid nitrogen levels.
“When Dr. Conaghan unplugged the controller, what he did was he placed the tissue in Tank 4 at additional risk that none of the tissue in the other tanks in his lab were subject to,” Miller told jurors from the witness stand.
After the controller was unplugged, Conaghan told lab workers to manually monitor the tank’s liquid nitrogen levels with a dipstick each day. Miller said that technique was inadequate because it did not provide 24-7 monitoring, and the tank was no longer connected to an alarm system to warn lab workers about problems. Miller noted that some measurements were missing or backdated in digital logs, suggesting the manual measuring system was not “well implemented.”
He also called attention to the fact that liquid nitrogen levels were recorded in tenths of an inch instead of eighths of an inch, which is how the dipstick measurements work. That discrepancy suggests the staff wasn’t taking accurate measurements, he said.
“I don’t think they were reading the numbers off the stick,” Miller said. “They were sort of guessing or guesstimating.”
Miller further faulted the fertility clinic staff for not immediately moving tissue samples into a backup tank when they discovered the tank’s controller device was malfunctioning on Feb. 15, 2018.
“If the controller was not providing the level of indication on Tank 4, the backup tank should have been put into service,” Miller said.
Miller also attacked theories about the cause of the tank failure posited by the plaintiffs’ expert witness. Mechanical engineer Anand Kasbekar testified on May 24 that the accident resulted from Chart’s use of a weaker weld near a liquid nitrogen inflow pipe, making the tank susceptible to cracking, leaks and failure.
Miller noted that in his 25 years of working with cryogenic systems, he’s never seen one that used a full-penetration weld like the one Kasbekar said should have been used on Chart’s tank. All the tanks he's worked with used seal welds, he said.
“I’ve never designed a full-penetration weld for a cryogenic vessel,” Miller said.
Miller also rejected Kasbekar’s theory that a defect caused a loss of integrity in the vacuum seal layer that separates the inner and outer walls of the tank. Kasbekar posited that the tank leaked a large amount of liquid nitrogen in 22 hours after it was last checked and before a problem was detected on March 3, 2018.
But Miller said it would be impossible for the tank to leak that much liquid nitrogen in that time span. It would be equivalent to venting 42,000 2-liter bottles of nitrogen gas in 22 hours, he said. The engineering professor further argued that if there were a vacuum seal layer problem, the staff would have noticed clouds of nitrogen fog spewing from the tank, frost forming on the vessel's outer walls and moisture pooling beneath the tank.
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