By Jay Zimmer The biggest challenge to the arrival of the COVID vaccine is keeping it cold. The Pfizer two-shot vaccine has to be stored at severely low temperatures, and Evansville Welding Supply — which also happens to sell dry ice — is ready to pitch in. Dry ice is made from carbon dioxide which is compressed in a device that forms the gas into a solid. The blocks are then sealed in containers for shipment — the seals prevent air from getting inside the super-cold containers. '); } return false; }); $('#comments .commentlist .comment-content a').attr('target','_blank'); });