It’s happened before, and it’s likely to happen again: a catastrophic failure in a liquid-nitrogen (LN2) storage tank, holding biological materials that are essentially irreplaceable. The odd coincidence of the event happening twice within a week, at two different in-vitro fertilization (IVF) clinics in the US, reinforces the imbalance between the relative simplicity and reliability of LN2 storage systems, and the harsh consequences of a failure. Class action lawsuits have been filed against one of the facilities—the University Hospitals Fertility Center, in Beachwood, OH—and are probably in store for the other, the Pacific Fertility Clinic in San Francisco.
Investigations are under way at both facilities, and details are sketchy. Based on various press reports, the Ohio center had a storage tank containing a couple thousand eggs and embryos, while the Pacific center had eggs and embryos of several hundred clients stored in a similar manner. According to the Cleveland Plain Dealer, the Ohio facility saw temperature fluctuations during the weekend of March 4, when the facility is unattended. An audible alarm apparently went unnoticed. At the Pacific center, a company manager noticed a low nitrogen level, and acted to transfer the stored materials to another tank. It’s not clear to what extent the eggs and embryos are damaged; the Ohio center set up a call-in number to coordinate with clients.
Across healthcare and life sciences research, LN2 dewars are a common method of storing biological samples. Typically, says Rick Kriss, president of Klatu Networks, the dewar is connected to an LN2 supply tank which feeds additional LN2 to the dewars as temperature and liquid-level indicators dictate. But there is no industry standard for alarms and monitoring systems; one industry expert cited in press reports indicates that the alarms at university medical centers are connected to campus security. “LN2 storage is very reliable and changes happen slowly,” says Kriss, “which implies that you’re already several days into an upset if an alarm is tripped.”
Kriss’ company has developed a cloud-based predictive-maintenance system for mechanical refrigeration systems, called TRAXX, that analyzes refrigeration compressor performance to predict when maintenance is needed; it’s now installed at several multinational pharma companies. (Mechanical systems generally operate down to -80°C; LN2 systems can maintain a deep-frozen, -196°C temperature at which all biological activity ceases. It’s worth noting that several steps involved in the latest cellular and genetic therapies being commercialized in biopharma involve LN2.) In recent months, says Kriss, a similar predictive system has been developed for LN2 systems. “Cold storage technology is usually a combination of equipment and human operators,” he says. “You need to manage the risks inherent in that combination.”