Some 20 years ago, in the heady days between the fall of the Berlin Wall and the collapse of the Soviet Union, aid officials from the U.S. got their first, long look at a region-wide environmental mess behind the Iron Curtain.

Throughout Central and Eastern Europe, visiting aid delegations found groundwater poisoned by diesel fuel and pesticides, air fouled by sooty smokestacks and agricultural soils doubling as dumps for industrial and military wastes.

The recent disastrous spill of millions of gallons of toxic red sludge from an alumina plant in western Hungary harks back to this earlier era of totalitarian unconcern. As a current member of the European Union, Hungary now is subject to the same environmental directives and regulations as the other 26 E.U. nations. However, like many of its former Eastern-bloc neighbors, Hungary has been slow to clean up Communist-era pollution, and particularly in rural areas, environmental measures at some state-owned and private enterprises have not changed much.

Farms, mines and brownfields in Europe’s eastern tier are pocked by ponds filled with toxic wastes. Tailings from refineries lie adjacent to tributaries of major rivers, such as the Danube, Vistula and Tisza, which endured a catastrophic cyanide spill in 2000. Accidents such as the alumina sludge spill in Hungary can affect the health and livelihoods of thousands of people, including citizens well downstream of the accident site.

The toxic mess in Hungary should serve as a warning to communities — not just in Europe — but throughout the U.S.

From the Deep South to the Upper Midwest, there are thousands of open-air lagoons containing sewage from farms, feedlots, and factory outfalls. The Environmental Protection Agency estimates there are more than 600 ponds and dams containing toxic coal ash.

A coal-ash dam that collapsed near Knoxville, Tenn., in 2008 discharged more than one billion gallons of heavy metal-laced ash — in volumetric terms, a bigger accident than the BP Deepwater Horizon spill earlier this year — covering hundreds of acres of farmland, damaging homes and generating a major health scare in three states.

Going forward, we can expect more such incidents for two major reasons:

• First, securing frail, poorly regulated retaining ponds is a relatively low priority on a tall list of to-dos for EPA and other agencies with environmental responsibilities.

• Second, global climate change compounds the risk of catastrophic spills. The Tennessee coal-ash spill was preceded by several days of heavy rain, which caused the earthen embankment around the dam to erode.

Climate-change experts predict more frequent, major rainstorm events in regions like the Upper Mississippi and Ohio River Basins — so-called “gully washers” that are sudden, intense and destructive.

The prospect of a combination of more frequent floods and the failure of flimsy retaining ponds is unsettling. Moreover, the damage is likely to occur in rural areas lacking the financial, technological and organizational wherewithal to easily recover from such catastrophes.

The toxic sludge that buried villages and waterways in Hungary is thousands of miles from American shores, but it is easy to imagine citizens of Roane County, Tenn., feeling empathy for the sludge victims. Many Tennesseans are still digging out from the 2008 coal-ash spill.

Much as Hungary needs foreign assistance to recover from its sludge mess, American citizens, particularly in rural areas, need federal assistance to prevent comparable accidents.

Stronger regulations, new waste-reduction methods and technologies and more durable waste-containment facilities are desperately needed now. Their costs represent a fraction of the costs to clean up disasters like the recent spills in Hungary and Tennessee.

The EPA and Congress should heed the timely lessons of Hungary and Tennessee and jump-start a rational process of sorely needed protections.