. >> reporter: and wayne cordal.ere denied benefits after negative x ray readings by one doctor at john hopkins hospital, dr. paul wheeler, an abc news investigation last year conducted with center for public integrity found of 1,573 cases, dr. wheeler on behalf of coal companies never found a single case of severe black lung in any coal miner. not one. >> i have no idea what happens once the x-rays leave my department. >> reporter: does it matter to you? >> it would matter to me if i was wrong. no one has proven to me i was wrong. >> reporter: our investigation found he has been wrong a lot. based on 100 cases of miners in which autopsies or biopsies later found black lung after dr. wheeler had not. days after our broadcast last october, johns hopkins suspended dr. wheeler's black lung program. now the department of labor which administers the miners' benefits program is taking more significant action because of our investigation. >> it was shocking. >> reporter: the labor department's top lawyer solicitor patricia