When I bought dry ice (last year) for the science fair, they do give out a safety brochure on handling. One of the top 5 points, no tightly closing containers.

When I bought dry ice (last year) for the science fair, they do give out a safety brochure on handling. One of the top 5 points, no tightly closing containers. Styrofoam cooler is ok and dry ice will last 2-3 days like that.