Hillhouse's Second Soil Peak: A Direction With No Stated Grid Spacing
The Phase 3 report sampled gardens south-east of the Hillhouse site on roughly a 50m grid and used a spacing of 200m or more beyond a 500m radius of the facility, built for coverage rather than detail. Within 500m, Phase 2 used 100m and 150m grids. The report's own data places its second concentration peak to the west-north-west, a direction for which it states no grid spacing.
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, commissioned to investigate PFOA and PFAS contamination 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.
One direction from the Hillhouse site was tested on a grid tight enough to tell one garden from the next. Beyond a 500m radius the report used a spacing of 200m or more, built for coverage, not detail, and within 500m Phase 2 used 100m and 150m grids. The report’s own data puts its second concentration peak to the west-north-west, a direction for which it states no grid spacing.
The report says, in its own words, how thinly it tested
Section 1.5, Scope of Work, describes how Phase 3 chose where to test: “A higher density of properties were selected to the south-east (approximate 50m grid spacing)… compared to a wider spacing (200m+ beyond 500m radius of the facility) within the wider area to provide coverage” (p.12). By the report’s own description, the wider grid existed to provide coverage. It was not built to characterise a hotspot closely.
Figure 1, the sampling location plan (p.49), shows exactly what that produced. The south-easterly grid is a dense cluster of points hard against the facility boundary. The wider grid, covering everything south, south-west, west and north-west within the same 1km buffer, is spread thinly across the map, points often hundreds of metres apart. Both grids sit inside the same 1km facility buffer. Within 500m, Phase 2 used 100m grids (south and south-east) and 150m grids (south and south-west). Their density differs.
Where the second peak actually sits
Later in the report, the combined Phase 2 and Phase 3 dataset is plotted by compass bearing (Insert 4-2, p.33). The report’s own text states that “the highest concentrations are c. 120˚ (south-east) and 280˚ (west-north-west) rotation” (p.32).
The south-east peak sits inside the dense grid. The west-north-west peak, at 280 degrees, is in a direction for which the report states no grid spacing. The report describes its wider spacing as “200m+ beyond 500m radius of the facility”, built “to provide coverage” rather than to resolve fine spatial detail near the source.
Why the spacing is not a technicality
A 50m grid can tell one garden’s reading from its neighbour’s. A grid spaced at 200 metres or more, the closest spacing the report gives beyond 500m, cannot make the same distinction. A single elevated reading inside a widely spaced grid does not tell you whether the ground around it follows the same pattern, or how far the pattern reaches. The report states no grid spacing for the direction holding its own second concentration peak.
We are not saying the reading is wrong. We are saying it has not been checked closely enough to know how far it extends.
That is the question the report’s own figures raise, read alongside its own orientation analysis: whether the west-north-west sector has been characterised closely enough to establish the true extent of the peak the report’s own data measures there.
We are asking this openly. We are preparing to put it formally to WSP and the Environment Agency, and will publish any response here.
How we know what we know
Everything above is drawn from one public document: the WSP Phase 3 Residential Soils Investigation, commissioned by the Environment Agency and published by Wyre Council in March 2026 (link above, so you can check every page). The grid spacing is the report’s own description in Section 1.5, Scope of Work, page 12, and its own sampling map, Figure 1 in Appendix A, page 49. The second peak is the report’s own text and chart at Insert 4-2, pages 32 and 33. We have added no sampling, no modelling and no new data of our own; we have set the report’s description of its own methods against the report’s own results.