Opinion ID: 519994
Heading Depth: 2
Heading Rank: 3

Heading: The EPA's Analytical Methodology

Text: 276 The analytical methods for measuring pollutants become unreliable at the low concentrations the EPA has established in the limitations. Two different laboratories, each using acceptable methods, may measure the pollutant in a given sample and reach different results, yet neither lab may be demonstrably wrong. This has been referred to above as analytical variability. Monsanto, Dupont, and CMA contend that the BAT limits cannot be achieved because analytical variability will in some instances inevitably result in a detection reading (or laboratory measurement) in excess of the limitations even though the true value of the sample is within the limits. 277 The EPA responds by asserting that analytical variability was adequately accounted for in its derivation of the BAT limitations. As previously discussed, the variability factors were derived from empirically-observed variations in measurements due either to analytical variability or to routine fluctuations in a plant's performance. To calculate the BAT limits, the EPA multiplied the long-term averages by the variability factor, and because it did so, the EPA asserts, its statistical model necessarily accounts for analytical variability. 278 The record shows, and the EPA concedes, that certain pollutants are subject to substantial analytical variability. In review proceedings, however, the burden is on the petitioner to show that the Administrator's determination was arbitrary, capricious, or an abuse of discretion. 211 The industrial petitioners have not shown that the variability factors the EPA assigned to the respective pollutants failed to account for analytical variability, and therefore the petitioners have failed to meet their burden.
279 Many of the OCPSF plants use a variety of processes to produce a number of different organic chemicals or plastics, and, as a result, the wastestreams from these plants include several pollutants, making the wastestreams complex. Monsanto and Dow contend that current analytical techniques cannot reliably measure low pollutant concentrations in a complex wastestream due to interference from other chemicals and that, therefore, the low effluent levels required by the BAT limitations cannot be achieved by their plants. 280 The EPA has developed comprehensive Guidelines Establishing Test Procedures for the Analysis of Pollutants, known as Part 136. 212 The EPA has determined minimum levels at which these analytical techniques can reliably measure the concentration of a pollutant without interference from other pollutants through a calibration process by which the known concentration of each pollutant is analyzed. The EPA has determined that the limitations are all well above the minimum levels for reliable detection. 213 281 The EPA purports to have accounted in this fashion for the problems of analytical uncertainty and interference from other compounds. Monsanto's and Dow's contentions amount to the argument that their studies are contrary to the EPA's and that their studies show the BAT limitations to be within a range that will be affected by analytical uncertainty and interference. This issue turns on a question of analytical chemistry that this court could not resolve without performing independent laboratory work, and that is beyond both its power and its technical capacity. When reviewing an agency's scientific determinations in an area within the agency's technical expertise, a reviewing court must be at its most deferential. 214 We defer to the EPA's determination of this issue. 282
Insufficient (Borrowed Data) 283 When the EPA had not obtained sufficient plant variability data to calculate the variability factor for a pollutant, it used the average of those variability factors that it had established for other similar pollutants or, if no such average had been calculated, for all of the pollutants subject to the BAT limitations. CMA contends that the EPA's use of this borrowed data to determine the variability factor for a pollutant when data were not otherwise available was sheer guesswork. 284 For the BAT 1 limitations, when data were not otherwise available, the EPA determined the variability factor by using data from pollutants exhibiting similar chemical structure and characteristics that bear on treatability. This was based on the reasonable assumption that similar compounds react similarly to similar treatment. For BAT 2 , when direct data were not available, the EPA computed variability factors by averaging the variability factors for all other pollutants that the EPA found to be treatable by the same technology. The EPA has established a reasonable basis for its use of borrowed data. 215 Its assumptions are logical and there is nothing in the record to establish that they led to scientifically inaccurate results. 285
286 Analytical Value to Assign to Non-Detect Readings 287 To calculate the long-term averages for plants in the data base the EPA included non-detect values. As previously discussed, the value assigned to a non-detect reading was the minimum analytical value. To derive the limitations for the polynuclear aromatics, the EPA assigned to these pollutants the published minimum analytical value of 10 ppb that appears in Part 136. 216 288 The BAT 2 limitations for the polynuclear aromatics were based on data from plant 1293T. 217 CMA notes that the EPA lab reported an average minimum analytical value of 13.3 ppb for this plant. CMA asserts that the published Part 136 minimum analytical values were determined based on pollutant samples in pure reagent water free of other interfering chemicals and do not account for real-world interference from other compounds that raise the minimum analytical value, such as the reported minimum analytical value at plant 1293T. CMA argues that the EPA therefore erred by using the published minimum analytical value, rather than the lab-reported average minimum analytical value for plant 1293T, and this error of 3.3 ppb made the limitations more stringent. 289 The EPA's methodology for deriving the effluent limitations included several conservative assumptions that created a margin for error and ensured that the limitations are achievable. 218 The first of these conservative assumptions is that when a data base plant reported a non-detect reading, the EPA assigned the minimum analytical value to such a reading. 219 By assigning the minimum analytical value, rather than zero, to plants that reported non-detect readings, the EPA raised each plant's long-term average above the true treatment level achieved by the plant. This resulted in higher, less stringent, limitations than would have been imposed if the EPA had assigned a zero to non-detect readings. 220 Second, in calculating the variability factors for each pollutant, the EPA did not use data from plants that consistently reported non-detect readings. 221 Consequently, data from the best performing plants were not used to derive the BAT variability factors, thus avoiding higher BAT limitations. The EPA's error, if any, in using the published Part 136 minimum analytical value, rather than the wastestream-specific value reported for plant 1293T, was, therefore, offset by the EPA's conservative methodology used to develop the BAT limitations. 290 The record shows that the BAT 2 limitations based on data from plant 1293T are achievable. 222 The lowest of the effluent limitations based on the performance of this plant is well above the minimum analytical level whether 10 ppb or 13.3 ppb is used. For instance, the BAT 2 maximum daily limitation for benzo(k)fluoranthene is 47 ppb, while the maximum monthly average is 19 ppb. 223 The data show that plant 1293T performed within these limits whether the minimum analytical value is 10 ppb or 13.3 ppb. 224 291 CMA also asserts that at least one plant reported minimum analytical values of 100 ppb for toluene and chloroethane and 60 ppb for chlorobenzene. CMA contends that the EPA erred by assigning the Part 136 minimum analytical value of 10 ppb to toluene and chlorobenzene and 50 ppb to chloroethane in promulgating the limitations. 292 The EPA asserts that the reported minimum analytical values of 100 ppb for toluene and chloroethane and 60 ppb for chlorobenzene were not representative of the data as a whole and that these data should have been excluded from its calculation of the limitations. The EPA attributed these extremely high minimum analytical values at one plant to dilution due to interference from other chemicals. The EPA's data-editing criterion was to exclude data from plants whose samples could not be measured down to the minimum levels listed in Part 136. Thus the data associated with the extremely high analytical minimums identified by CMA should have been excluded. If these data had been excluded the limitations would have been the same, based on the remaining data, because in calculating the limitations the EPA relied on the median performance of the best plants and the vast majority of the readings for toluene, chlorobenzene, and chloroethane were non-detect readings with minimum analytical values equal to those assigned in Part 136. 225 Because the limitations based on the other data would have been the same even if the EPA had excluded the objectionable data, the EPA's error in including these data in the data base was harmless.
293 The EPA's analytical methods for determining pollutant concentrations were developed during the rulemaking period. Part 136 was later amended to provide newer, more accurate analytical methods. Monsanto argues that applying one analytical method for the development of the OCPSF limitations and another more accurate standard for enforcement produced anomalous results and that, therefore, the limitations are arbitrary. 294 Current Part 136 outlines several approved analytical methods reflecting both old and new methods for measuring pollutants. An industry member that believes it can record lower measured pollutant-effluent values using the older methods is permitted to do so. 226 Because Part 136 provides industry members with a choice of several analytical methods for reporting purposes, the industrial petitioners were not prejudiced by changes in analytical methods in the development of the limitations. 295