On the chemical tankers, we often check empty compartments for cleanliness before certifying suitable to load sensitive industrial chemicals. Especially after

On the chemical tankers, we often check empty compartments for cleanliness before certifying suitable to load sensitive industrial chemicals. Especially after they imported some of those nasty food grade commodities. This requires more than just standard laboratory methods. Turns out I am one of the pioneers of this. Haven't chemically sampled compartment walls myself in years, but it's dark down there with only small access openings in the deck overhead, climbing down a very tall vertical ladder with your gear then back up with your samples. You need a safe, reliable industrial operator with explosion-proof equipment, and very judicious sampling approach. For decades I've heard that cleaning and testing delays are easily overcome in many parts of the world where the presure to expedite the movement takes form in ways which would be considered irregular in my port.