An Ohio fertility clinic said that the remote alarm system on its storage tank was turned off, so it didn't know that the temperature had fluctuated, and that the consequences were worse than it initially thought — all 4,000 eggs and embryos in the cryofreezer are likely nonviable.In a letter to affected patients on Tuesday, the University Hospitals health care system wrote: "[W]e have determined that the total number of affected eggs and embryos for these patients is more than 4,000, not the estimate of 2,000 previously used. We are heartbroken to tell you that it's unlikely any are viable."University Hospitals said its investigation into the incident on March 3 to 4 at its fertility clinic in suburban Cleveland suggested the problems might have been caused by human error, mechanical failure or both.The first problem was that the remote alarm system on the tank, designed to alert a staff member if there were swings in temperature, was turned off."We don't know when the remote alarm was turned off," the letter explained, "but it remained off through that weekend, so an alert wasn't sent to our employee as the tank temperature began to rise on Saturday night, when the lab isn't staffed. An alarm should have been sent and received. We don't know who turned off the remote alarm nor do we know how long it was off, but it appears to have been off for a period of time."The letter also said the tank that failed needed preventative maintenance. The tank had been having issues with the mechanism is that is supposed to automatically refill the liquid nitrogen to keep the specimens cold. As a result, the liquid nitrogen was being filled manually."On the Friday before the weekend of the failure, the liquid nitrogen was brought in a container from the nearby Andrology Lab and poured into the tank," the letter says. "The liquid nitrogen levels in the tank were monitored and appeared to be appropriate on Friday and Saturday, but we now suspect that may not have been the case."Just before the tank failure occurred, the clinic had been preparing to move all the specimens to an extra storage tank to perform maintenance on the automatic fill.Dr. James Liu, chairman of the hospital system's department of obstetrics and gynecology, told the Cleveland Plain Dealer that the clinic was "about a day or so out" from moving the eggs and embryos when the failure happened.The hospital system says it is refunding storage fees to those patients who had stored eggs and embryos, as well as offering tailored emotional and medical support, including a free round of IVF for those who want it. The hospital system isn't asking patients to sign a release in order to access the services.In a video statement, Tom Zenty, the hospital system's CEO, apologized for the failure: