I was working in the US Geological Survey in the Water Resources division and we were asked to look at a proposed solution to shipping water samples from the field to a testing facility. The proposed container was similar to what is in the picture here except it was much smaller than the 30 gallon drum in the picture. It was about 24 inches high and maybe 18 inches in diameter. It was made of steel so it was very strong. The lid was loose but could be attached to the drum with the clamp you see resting against the side of the drum. It seems silly, in retrospect, to have thought about shipping something that big and heavy via the post office but that's what we were asked to do.
We thought about various ways of keep it cool for the whole trip. I forget what the target length of time was but let's say it was a week. We figured the final product would be heavily insulated but that might not be enough. So, we tried packing ice in the container. No matter what we did, though, the ice would melt and make it very difficult to keep out of the insulation and to keep from contaminating the water samples. Of course, one solution would have been to use frozen gel packs encased in plastic like you see in food coolers but I don't think we had access to those back in 1975 or so. So, our next goal was how to keep the ice from melting. Our first thought was to use dry ice, in a separate waterproof container, to keep the water ice from melting. We had already drilled a hole in the top of the canister so we could slip a temperature probe into the container so we could monitor the temperature over time. We had a rubber grommet in the hole so the sharp edge of the metal wouldn't damage the temperature probe. So, we figured, this would act as a safety valve for the expanding carbon dioxide when the dry ice warmed.
We started the test and it looked good at first. The temperature stayed nice and cold and we didn't hear any sloshing around when we moved the can. But days later, I noticed that the top of the canister was bowing up. It looked like our "safety valve" wasn't working (I must have picked a grommet too close in size to the temperature probe's cable) and the carbon dioxide was putting quite a lot of stress on the container. So, I unfastened the screw clamp to open the lid. But even after I loosened the screw all the way, I couldn't get the lid off. This couldn't be good. Maybe I should have tried drilling another hole in the lid but that would take too much time. So, I started tapping the clamp with a hammer to loosen it.
All of a sudden, there was a BOOM. The lid hit the ceiling and ice, some water and what remained of the dry ice flew everywhere. People from all over the place came running to see what had happened. Nowadays, with an explosion occurring in a government facility, I'm sure the police or building security would have been called. But all that happened was that we had a lot of cleaning up to do and we looked kind of stupid. I think that project was taken away from us, too. I don't remember. But I do know we never assumed that a hole with a grommet would act like a safety valve again.
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