The occupational health hazards of asbestos were defined through research and epidemiology studies in people who demolished ships for scrap thus being exposed to plentiful asbestos used as fireproof material in ships, mainly in their propulsion systems. These people were called ship breakers and the occupation ship breaking.
These studies were accomplished in Baltimore, among other places, where retired union workers were easily contacted and willing to participate in grant-funded studies at no expense to them. A lot of the workers had been employed dismantling ships after World War Ii in the 1950's.