The pair of incidents, with powerful emotional and financial consequences, come as the number of US women freezing their eggs has soared in recent years as assisted reproductive technology has advanced and become increasingly popular.
The hospital estimates about 2,000 frozen eggs and embryos may have been damaged or destroyed by a storage tank malfunction. Herbert said the problem was "immediately rectified", and he also praised the clinic's decision to replace the troubled tank with the new one.
Patti DePompei, president of University Hospitals Rainbow Babies and Children's Hospital and MacDonald Women's Hospital, called the situation "absolutely devastating". It's not clear how the affected patients will be compensated.
According to Herbert, the extent to which the chemical failure damaged the eggs and embryos remains unclear.
Samples would need to be unthawed to determine whether they've been damaged.
The hospital has issued an apology after the unexplained malfunction caused temperatures inside the storage tank to rise. Embryos - fertilized eggs - are stored individually.
It is the second clinic to report a fault that weekend.
In a statement, the Pacific Fertility Center said "viable tissue" had been recovered from the one tank affected and that "the vast majority of the eggs and embryos in the lab were unaffected". The clinic also has brought in a multidiscplinary team to investigate the tank itself and "every aspect that involves cryopreservation", he said. "This was a bad incident", Herbert said, "but I was reassured that.he did everything anybody could ever want to do".
An attorney for the Ashes, Mark DiCello, said patients have "too many unanswered questions".
"At this point, we do not know the viability of all the stored eggs and embryos, although we do know some have been impacted", DePompei said in a video statement posted on Facebook.
Sean Tipton, chief policy, development and advocacy officer for the American Society for Reproductive Medicine, which represents people working in fertility clinics, said the first priority is to work with patients to see if some of their eggs or embryos were stored in other tanks or at other facilities.
According to the clinic's website, its fees for egg freezing are $8,345 for the initial cycle and $6,995 for each subsequent round. Patients typically pay about $12,000 without insurance for in vitro fertilization. He moved to San Francisco in 1990 and, with colleagues, purchased Pacific Fertility Center nine years later.
An Ohio couple is suing University Hospitals' Fertility Center in Cleveland after learning their embryos have been damaged because of a storage tank malfunction. Some dated to the 1980s.
"I just urge everyone, before you judge what they've gone through, or what they're going through, or what their motives for doing it, ask yourselves, 'What would it be like if I had my family's treasure lost by a hospital that just didn't care enough to check on it?'" DiCello said.