Since the mid-1990's, the trend in dealing with remediation of contaminated sites has moved toward risk-based decision making.

Notably, state environmental protection agencies have moved from the philosophy of "dig it all up" to either "dig the worst and control the rest" or simply, "let it be". These strategies assume that only a very limited environmental risk is left by what is not dug.

Why has this change occurred? What are the best ways to react to these changes?

First, and foremost, regulations have changed. "Risk Based" has become the norm due to three practical considerations:

  1. There were too many sites to handle with more strenuous strategies;

  2. There was too little money available to carry out those strategies; and

  3. There was really no compelling reason, anyway.

Too Many Sites

From a practical standpoint, there are just too many sites with some degree of contamination, notably in older industrial cities.

Using Chicago as an example, with the "dig it all" philosophy of 8 – 10 years ago, a case could have been made by the regulatory community that virtually every square inch of the metropolitan area would have to be dug up and hauled away.

Even those of us who live in the City of Chicago itself probably have some degree of contaminant in our back yards. Should we have to dig this up and haul it away? That doesn't seem reasonable.

Where would all this contaminated soil be hauled away to?

Too Little Money

The cost of the dig-it-all remediation philosophy did not really strike home to the regulatory community until the State Reimbursement funds for USTs started running out of money. Pretty soon thereafter these rules began to change. It was pretty hard to require that a voluntary cleanup of a non-reimbursement eligible site be performed to a tighter standard than for sites on which an agency was going to provide remediation monetary assistance.

Thus, if in 1993 a State Reimbursement fund required that 80% of all UST sites to clean up down to close to background, and there was money for only 20%, those sites that were not "in line" early had to stand and wait. And, as more sites entered the reimbursement programs, that wait lengthened and lengthened, until it became intolerable.

No Compelling Reason

As regulators and scientists reevaluated cleanup objectives, it became apparent very quickly that, in many cases, there simply was no compelling need for full remediation, and in some cases, for any remediation whatsoever.

Perhaps a site was covered by 12" of concrete. Perhaps the contaminant had been in the ground for 90 years, hadn't migrated anywhere, hadn't hurt anyone in all of that time, and wasn't moving anywhere.

Equally as important there simply wasn't an aggressive push from society as a whole to clean sites with low or minimal risk. As our air and water have indeed become cleaner over the past 20 years, society's demands for continued enhancement in certain areas have lessened, or minimally, changed.

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