New York State Tenement House Act

Among other sanctions, the law required that new buildings must be built with outward-facing windows in every room, an open courtyard, proper ventilation systems, indoor toilets, and fire safeguards.

Jacob Riis, in his ground-breaking, muckraking journalistic expose of 1890, How the Other Half Lives: Studies Among the Tenements of New York attributes the reform movement to the fear of contagious disease emanating from the ghettos, especially following an outbreak of smallpox, far more contagious than the cholera and tuberculosis that had long dwelt in the Lower East Side of New York, the hub of immigrant ghetto life.

He views the laws and the progressive reform movement that motivated them as a confluence of the cynically-minded with the civic-minded, eventually working towards the benefit of the burgeoning city's labor force.

[1] The reform movement culminated in a prominent Tenement-House Exhibit of 1899 held in the old Fifth Avenue Sherry's, a Gilded Age center of elegant society.

The curious sandstone faces and gargoyles and filigreed terracotta of the previous twenty years of tenement design gave way to the more abstractly classical ornamentation of this urbane, international and more grandiose Parisian style.