What occupation puts one at risk for black lung?
Coal seams Collieries Coal miner Coal mines Colliery Coalminer Coal mined Surface coal mine Coal Mining Coal-miner Coal mine Coal extraction Environmental impact of coal mining Coalworks Deep mine Underground coal mining Coal pit Coal mining Coal-mine Highwall Opencast coal mining Coal production Mining coal Coalmining Coal seam Coal Miner Opencast coalmine Coal field Coal-mining Coalmine Underground coal mine Environmental impacts of coal mining