Though a study is under way, Puerto Rican officials say that at this point no one knows the extent of the damage or how expensive a cleanup would be.

The industrial history meant the soil was highly polluted and needed expensive cleanup before any residents could live there.

Officials were worried that the location would be polluted and would require an expensive cleanup.

Sloppy demolition led to burst water mains and expensive cleanups.

But such radiation could contaminate valuable real estate and could require expensive cleanup or abandonment for decades.

An even more expensive cleanup, costing around $7 billion, is under way in a northwest Denver suburb where plutonium triggers for America's atom bombs were made until 1989.

State's Costliest Cleanup The agreement, announced Wednesday, settled the largest and most expensive cleanup of hazardous wastes in Minnesota.

The problem, particularly in Kings Park, has been lingering industrial debris - asbestos, lead and other chemical hazards that require an expensive cleanup before any new construction happens.

Lieutenant Governor Murphy has depicted herself as the only liberal in the race, willing to raise taxes to resolve the state's budget crisis and press forward with the expensive cleanup of Boston Harbor.

This would be about 10 times more costly than the next most expensive toxic cleanup.