The oil boom in North Dakota has brought tens of thousands of workers to the state and transformed the economy. But the numbers of workers, and the dangerous work they do, have put great pressure on local healthcare services, from hospitals to ambulance crews.

Independent radio producer Todd Melby has been working on a series, “Black Gold Boom.” In Killdeer, a town in western North Dakota where the Census counted 751 residents in 2010, he talked with Ann Hafner, director of the Killdeer Area Ambulance Service, about the changes she’s seen.

Marketplace is airing a series of Todd’s vignettes of people and scenes from the boom region.

Todd Melby’s series, “Black Gold Boom,” is an initiative of Prairie Public and the Association for Independents in Radio.