Hazard Evaluation - DOE-STD-1120-1-20050032

DOE-STD-1120-2005/Vol. 1

of chemical form and concentrations. However, it is the total quantity that determines the initial

hazard categorization. For large area soil restoration sites where the material is dispersed

throughout the soil, surface, and groundwater matrices, historical process knowledge of the

material and types of activities that created the soil contamination may provide an initial baseline

for deriving the restoration activity inventory. However, in nearly all cases, the process

knowledge will have to be supplemented by survey data collection and analysis in order to

reduce the conservatism that is required if historical process knowledge is the only source of

information. Typically, a single "worst case" sample concentration, when multiplied out by the

volume, provides ultra conservative bounding inventory that can be reduced by consideration of

the process knowledge, available survey data, and available sample data. Only in the case where

statistically valid sampling shows a highly uniform distribution, should average concentration

values be used as the basis for the inventory. The basis for the inventory estimates needs to be

described in sufficient detail to allow reviewers to follow the methodology and arrive at a

conclusion of acceptability.

Inactive waste sites (IWS) that are subject to the Resource Conservation and Recovery Act or

Comprehensive Environmental Restoration and Cleanup Liability Act, covered with soil or other

engineered barrier, and don't involve active restoration are not expected to pose significant

localized, on-site or off-site consequences. These sites are simplistic in nature, and share similar

safety features, operational characteristics, and hazard potential. Therefore, a generic HA and

final hazard categorization has been performed by DOE for applicability to IWS operations

across the DOE complex. The basis and results are provided in Appendix D and can be used as

long as an IWS meets the definitions and conditions as specified.

Other environmental restoration activities may also have a high likelihood of being downgraded

to less than HC3 based on methodologies described in NSTP 2002-2. It may be a simple matter

to qualitatively demonstrate in a final hazard categorization that non-intrusive environmental

restoration activities (e.g., soil capping) pose no dispersive energy sources. It may also be

possible to demonstrate through segmentation that certain intrusive environmental restoration

activities can't physically exhume sufficient quantities of material at risk to trigger HC3

threshold values based on a final hazard categorization. In any case, assumptions in a final

hazard categorization require protection to maintain the DOE approved hazard categorization

valid. This could include physical limits on material at risk, as well as any changes to

assumptions on material form or dispersibility.

Segmentation techniques, as permitted by DOE-STD-1027-92, may also be employed in final

hazard categorization determinations, where physical structures or activities have independency.

This may be the case for intrusive environmental restoration activities that have physical

limitations on the Material at Risk (MAR) that can be exhumed at any one time. For example,

removal of contaminated soil may be limited by the volume that can be transported to a

designated treatment, storage, or disposal facility.

4.2.2.2

Hazard Evaluation

The results of the hazard and accident analysis should present the accident events and initiators

considered, estimated frequencies, unmitigated consequences and preventive/mitigative controls

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