Some insecticides are as poisonous to people as they are to pests — Page 100, Lesson 153

I want to walk you through a topic that isn't normally carried on commercial aircraft but can still cause serious health problems: hazardous substances you might encounter in aviation. Let's start with insecticides. Some insecticides are as poisonous to people as they are to pests. Even at very low trace levels, exposure can result in vomiting, diarrhoea, tremors, and coma. So these are not something to take lightly. Now, mercury. Mercury is exceedingly corrosive and poisonous, and on top of that, its vapour is highly toxic. You'll still find mercury used in instruments and gyro-erection systems on a number of older aircraft. In modern aircraft, you might find it in the thermometer that's carried as part of the first aid kit. So it's still present in the aviation environment. If you ever come into direct contact with mercury, you should immediately wash the affected area in quantities of hot water, followed by soap and hot water. That's the immediate first aid. But if you inhale the vapour, that's a different story — immediate and urgent medical treatment must be sought. Don't wait. Now, here's why mercury is especially dangerous in an aircraft. A mercury spillage can lead to catastrophic results. It attacks aluminium through a chemical reaction known as amalgamation. In this process, the mercury attacks the grain of the aluminium alloy, and in an exceedingly short time, it will completely destroy it. That's structural damage. Worse still, mercury will flow through minute cracks to get to the lowest part of the structure, where it will sit and cause extensive damage that you might not even see at first. So extreme care must be exercised when removing a mercury spillage. On no account should you attempt to blow it away with compressed air — that will only scatter the mercury and increase the risk of further damage. The best method is vacuuming. Finally, batteries. If batteries are fitted incorrectly, they can leak corrosive liquid and dangerous vapours. So correct installation is not just about electrical function — it's a safety issue. Let me show you a diagram of the gastro-intestinal tract, which relates to the gas problems we discussed earlier — the main problem is gas in the small intestine, which has no easy exit at either end. `` That covers the key hazardous substances: insecticides, mercury, and battery leakage. Each requires specific handling and awareness.