Dry Ice is around -100F. So anything in the ice chest will freeze SOLID. We do a yearly trip down the lower salmon ~ 6 days in 100+ temperatures. Have used dry ice several times with mixed results. One year a friend took a piece and put in his chest, froze the broccoli dip so hard it was like a brick. We have since used it as a 4-or 5 day chest. We take all the frozen main dishes that we will use on days 4-6, add dry ice, usually a block 6"cube, then fill remaining space with frozen milk jugs. Then 3 or 4th day out we open, devide all the ice and frozen food. We duct tape the cooler and shove in the bottom of someones boat, not opening until we seperate it out. It has worked fairly well. Good ice chest management work about a well. Just don't put dry ice in your chest with items you don't want frozen, including beer, as it WILL freeze them and will split the cans sometimes. We have had no issues with the CO2 expanding. Becarefull as it burns skin on contact!!!