A problem that cost us hundreds of manhours and tens of thousands of dollars when nobody checked the contents of "Medical Supplies" before loading. In the end we cut out the frames and re-skinned the aft cargo belly -- twice. You can find the extent of the spillage by using Flowers of Sulphur, mixed into a paste and spread all over the suspected area and beyond. The paste dries on yellow and is harmless but amalgamates with any minute amounts of mercury to form various sulphides of mercury clearly seen as black patches. This makes the full extent of the contamination visible. Then you get out the saws drills and rivetting guns, there's no safe way to clean it up! The mercury gets in everywhere and if you don't re-build, the affected parts are eaten away faster than the "C" Checks come round.
Be careful working in the area, mercury vapour will be in the air and it can be absorbed through the skin. It is a very nasty poison and once in the body Mercury is not excreted, you just build up a lifetime dose. Good Luck!
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Info noted. Plse report further.