Opinion ID: 1176318
Heading Depth: 2
Heading Rank: 3

Heading: Characteristics of the House

Text: Although OAR 345-50-035 sets forth certain characteristics that a house built upon the waste is assumed to have  an 8-foot high ceiling on the first floor, one complete air change per hour and a foundation constructed so as to meet the Structural Specialty Code  the rule does not describe the house in detail. The rule provides generally that [n]o consideration will be allowed for any special construction or treatments designed to reduce radon diffusion into the structure. EFSC interpreted this general provision to require the use of a reasonable hypothetical house. In its order, EFSC described the characteristics of a reasonable hypothetical house as follows: In determining unspecified characteristics of the hypothetical house and the values used in calculating annual average [radon-222] concentrations, we are guided by the following principles. The hypothetical house should be (1) of a type which one would reasonably expect to be built in the Pacific Northwest; (2) one which would not be overly complex to model; (3) one which would not result in unusually high or low radon concentrations; and (4) one which is built to comply with the applicable Uniform Building Code in all respects. We believe that a house meeting these criteria is most likely to accurately predict the hazard posed by particular wastes. EFSC also interpreted the rule to require the hypothetical house to have the most common type of foundation among houses now being constructed in the Pacific Northwest. On the basis of evidence in the record, EFSC determined that a 1,250 square foot house with a crawl space foundation was a reasonable hypothetical house that could be used to predict radon-222 concentrations. [11] Petitioners' principal objections to EFSC's characterization of the hypothetical house are that many houses are not built and maintained to code and that approximately half of all houses have basement or concrete slab foundations (also permitted by the building code) rather than crawl space foundations. Petitioners contend that houses not in compliance with the building code or that have basement or concrete slab foundations are more likely to have higher radon-222 concentrations and that EFSC should have taken into consideration these other constructions, perhaps through a weighted-average technique. While petitioners' suggestions, if adopted by EFSC, might have produced a more realistic, albeit complicated, assessment of the danger presented by TWCA's waste, we cannot say that EFSC's interpretation of the rule is erroneous. The rule requires only that the hypothetical house have certain limited characteristics and that it not be specially designed or treated to reduce radon-222 diffusion into it. In essence, the rule requires a house that is in some sense reasonable or typical. EFSC's necessary elaboration of the characteristics of the house is consistent with the rule.