EAST CHICAGO, Ind. (AP) — A mayor’s abrupt order to evacuate a 40-year-old public-housing complex because of severe lead contamination led many to wonder: How could the problem have been overlooked for so long?

It turns out the hazard wasn’t — or shouldn’t have been — a surprise to anyone in public office in East Chicago or responsible for residents’ safety. The northwest Indiana apartment complex was built on ground once occupied by a lead-products factory. Some yards had lead levels more than 70 times the federal safety standard.

A review of documents and news coverage dating to the 1960s shows officials at a half-dozen local, state and federal agencies were aware some 1,000 residents were living on lead-tainted soil, though some of the most alarming readings weren’t widely known until recently.

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