we had a military contract for radio boxes that fit into back packs. made out of aluminium. to prevent corrosion they had to be plated. Alochrom is normally the choice but we had to use mildef anadol (the chrom missing is chromium).
reason being is....
if a soldier had one on his back and was shot, and bullet passed through the box the military/government were not concerned with the bullet killing said soldier, the worry was, the soldier dying of chrome poisoning to which they would be held to account not the enemy, therefore liable for his death.
our brake units were Anodized and stained with DiChromate, the Chinese, our big customer complained because we knew chromate was being phased out BUT the Chinese liked the colour and did not want different colours on the same wheel bogies. SO we had to consult with all our platers to come up with a solution that protected and gave the right matching colour. There was a 2 year buffer to allow stocks to end and new to come in, unfortunately, we still managed to cut it to the last minute before we arrived at the right solution.