However, additional asbestos contamination was found outside the Johns-Manville property which will require further cleanup.

Typically 10 percent of these parcels will prove to be contaminated and require containment or cleanup, according to government regulators.

Not only will this require extra cleanup; the glue will penetrate the wood and leave stains.

In a statement, the city's lawyers estimated that 4 of every 10 children in areas that had required cleanup suffered from lead poisoning.

Most do not contain significant amounts of radioactive contamination and do not require cleanup.

In addition, the Board of Education has had trouble finding enough sites for new schools, and those they find sometimes have environmental problems requiring extensive cleanup.

Potential purchasers are often unwilling or unable to risk an investment in a site assessment for a property that may require cleanup they cannot afford.

Abandoned chromium production sites often require environmental cleanup.

There are other large sites, some even better situated, but many are brownfields, where previous industrial developments left environmental problems that require cleanup.

Until now, every school inspector had checked had at least some exposed asbestos requiring cleanup.