In 1909, an organization called the Anti-Tuberculosis League of King County began its fight against the disease, employing nurses to survey the community. Horace Henry, president of the League, donated a 34-acre tract, 12 miles north of downtown Seattle, and $25,000 towards a sanitorium. The County Commissioners allocated $4,000 towards building and equipment and Seattle issued a bond of $10,000. The Anti-Tuberculosis League turned the sanitorium complex over to the City. The New Firland Sanitorium opened in 1914. In 1928, the County opened the King County Tuberculosis Hospital (Morningside) in Georgetown. In 1946 the City transferred control of Firland to the County. The County acquired use of the Naval Hospital in 1947 and relocated its sanitorium to that site.

In 1948, the Seattle Area Chest X-ray program was created. It was sponsored by the King County Medical Society, Anti-Tuberculosis League of King County and the Department of Public Health, with the cooperation of the U. S. Public Health Service and the Washington State Department of Health. Seattle was the first large city on the west coast to conduct the rapid tempo mass chest X-ray survey.

By 1954, the Seattle-King County death rate from tuberculosis had decreased by 82% since the introduction of the chest x-ray program. Case finding also had been increased by the operation of a miniature chest x-ray machine in the City Jail. In 1958, the Department's mobile x-ray units were managed as a separate section of activity in Health Education. In 1962, the Operation Double Check program combined tuberculin skin testing with chest x-rays.

Seattle University students line up to receive chest x-rays from a Public Health mobile clinic (see photo.) Called "a victim of its own success" in Public Health's 1971 Annual Report, the last Mobile X-ray Unit in the State of Washington was retired in 1971.

Chest X-Ray Van, 1960