Frozen embryos, eggs and semen cross borders every day. The paperwork, the dry shipper and the handovers that decide whether they arrive viable, explained by a cold chain supplier of 40 years.

Liquid nitrogen is colourless, odourless and inert, and that is exactly why it is underestimated. What LN2 is, the hazard that actually causes fatalities, and the handling discipline professional facilities live by.