A 2-year investigation by the Associated Press found that at least 1,680 dams across the United States pose risks to the residents in the areas surrounding them. The AP reviewed federal data and identified a number of dams that are rated in poor or unsatisfactory condition.

The AP noted that the number of dams in dangerous condition is likely much higher—some states declined to provide ratings and some states don’t have ratings to provide. The average dam in the U.S. is more than half a century old, and the AP reported around 1,000 dams have failed over the past 40 years.

The issue is indicative of a larger, failing infrastructure, and while the country is enacting measures on a state level to improve various infrastructure challenges, the federal government has yet to pass an overarching plan.

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