Maine’s Center for Disease Control and Prevention and the U.S. CDC are working with Operation Warp Speed to determine how 4,400 doses of Moderna’s coronavirus vaccine that arrived in Maine exceeded their temperature requirements.

Maine CDC Director Dr. Nirav Shah says they determined about 35 shipments arrived Monday with a thermometer reading on the boxes that indicated the vaccine had at some point exceeded the temperature required to keep it safe and viable.

Shah says it’s unfortunate to see logistical issues like these come up, but touted the thorough safeguards and processes that are in place to quickly alert them of such issues. He says those doses were separated, and replacements were being delivered Tuesday and Wednesday.

He says Moderna will look into whether those doses can ultimately still be administered.