Army Gen. Gustave Perna, who oversees logistics for President Donald Trump’s vaccine program Operation Warp Speed, told reporters that two trays of the vaccine that arrived at two separate locations in California had to be returned to Pfizer after the temperature somehow fell to minus 92 degrees Celsius.

The vaccine “never left the truck,” he said during a news briefing Wednesday. “We returned them immediately back to Pfizer and we sent immediate shipments to replace those two trays. We’re working with the FDA now, CDC, FDA and Pfizer to determine if that anomaly is safe or not, but we’re taking no chances and we can see that.”

He said the “anomaly” happened again in Alabama.