The Hillhouse Report Calls Its Quality Control 'Effective.' No Numbers.
The Phase 3 report describes its own quality-control results in reassuring language: trace contamination in some field blanks was 'not considered to be significant', and a failed laboratory recovery check was 'indicative only'. The numbers behind both statements are in the report. The reassurance is not built to show them to you.
From the Environment Agency’s Phase 3 soil investigation of the Hillhouse site.
Every figure and quotation below comes from the public version of the WSP Phase 3 Factual Report, the investigation into PFOA and wider PFAS contamination found in soil around the AGC Chemicals Europe (formerly ICI) plant at Hillhouse, Thornton-Cleveleys, published by Wyre Council: wyre.gov.uk/downloads/file/2452/phase-3-factual-report. Page numbers refer to that PDF, so the underlying page can be checked directly.
Thirteen out of 109. One analyte, below half its target. Both numbers are in the report. Neither is in the sentence that tells you the quality control passed.
The blanks that were meant to come back clean
During Phase 3, WSP took 109 rinsate samples, water run over cleaned field equipment between properties, to check that the decontamination process between samples was actually working (p.36). A clean pass looks like every one of those samples coming back below the laboratory’s limit of detection. Thirteen of them did not: “concentrations of PFAS analytes were below the LOD, with the exception of low-level concentrations reported in 13 samples” (p.37). The report’s own conclusion is that this “is not considered to be significant in the context of the dataset and overall, the QA/QC processes were deemed effective” (p.39). That may well be the right conclusion. It is stated as a conclusion, not shown as a calculation a reader can check against the 13 numbers themselves.
The one laboratory check that did not pass
Separately, the laboratory’s own accuracy checks, its analytical quality control (AQC), are reported to have passed for every compound tested, with one exception: “recovery of 6:2 FTAB in the quality control samples has observed to be <50% of the target value. The result is therefore indicative only. The remaining AQCs are within the acceptable ranges” (p.39). In plain terms, when the lab tested itself against a known quantity of this one compound, it recovered less than half of what should have come back, a result significant enough that the report itself flags the number as unreliable. The report adds that this “won’t have affected the levels of the contaminants in the actual samples” (p.39). Again, that may be entirely correct. It is asserted, not demonstrated with the underlying recovery figures set out for a reader to weigh.
We are not saying the quality control failed. We are saying the reassurance doesn’t show its working.
This is not a claim that the site’s contamination data is unreliable, or that these two results should change anyone’s understanding of the risk. A consultant’s report is, by its nature, written in one safe direction on questions like this: “not significant”, “indicative only”, “won’t have affected the results” are the only conclusions a report like this is ever going to reach, because the alternative would mean redoing the fieldwork. That is not a criticism of WSP specifically, it is how this kind of document is written industry-wide. Our point is narrower. The report states its own conclusions about the reliability of its data. It does not set out, in the same place, the numbers a reader would need to check those conclusions independently: what the 13 rinsate results actually measured, or what percentage the 6:2 FTAB recovery actually reached.
The question worth asking
What were the 13 rinsate concentrations, and how were they compared against the soil results from the same properties to reach “not significant”? What was the actual recovery percentage for 6:2 FTAB, and was that compound tested for, and detected, in any of the residential soil samples themselves?
We are asking this openly, and putting it directly to WSP and the Environment Agency. Any response will be published here.
How we know what we know
Everything above comes from one public document: the WSP Phase 3 Residential Soils Investigation, published by Wyre Council in March 2026 (link above). The rinsate sampling and its stated result are on pages 36 to 39. The laboratory AQC finding on 6:2 FTAB, quoted in full, is on page 39. We have not calculated, estimated or reconstructed anything here. We are quoting the report’s own words about its own quality control, and pointing out what those words do not include.