As long as "approved for tanks" lead paint is in the supply chain, who exactly keeps the use only to tanks. There are sufficiently durable alternatives that the lowest cost is to outright ban lead paint instead of setting up an enforcement framework to chase lead paint abuse while also paying added costs for after effects of easier cheating.

the workers who build and tear it down. maintenance workers. the chips and bits the wear off and get into the environment. and for a ships hull? the bits that get into the ocean and then sea life.

Sure you could argue that its small and harmless, but is it? can you prove it?

And, all that aside, there is an increased cost of all the precautions that need to now be taken when working with it offsetting the cost savings, as well as its now hazardous waste when torn down.