Swedish environmental practice exhibits a paradox where excavation and landfilling dominate per- and polyfluoroalkyl substances (PFAS) remediation despite evidence that in situ stabilisation achieves equivalent exposure risk reduction at substantially lower cost. This article examines whether legal uncertainty rather than technical or economic factors drives this pattern. Through traditional legal method, the analysis identifies structural ambiguities in the Swedish Environmental Code (SFS 1998:808) (SEC) that systematically favour technically inferior approaches. Two distinct gaps create legal uncertainty: Swedish law provides no clear criteria for distinguishing between preventive measures under Chapter 2 and remediation under Chapter 10 when stabilisation requires long-term active management. Additionally, Chapter 10 establishes no framework for determining when remediation obligations are fulfilled if contaminants remain in place under indefinite management while risks are adequately controlled. These gaps create asymmetric liability exposure where stabilisation achieves superior environmental outcomes but generates indefinite legal obligations, whereas excavation provides definitive liability termination despite relocating rather than managing contamination. The findings demonstrate that operators may rationally optimise individual liability management rather than environmental protection when legal frameworks cannot accommodate technical realities. Resolving this paradox does not require untested legal innovation. Swedish law's nuclear waste and mining liability structures demonstrate that indefinite management can be operationalised through financial assurance and graduated responsibility. While PFAS present a distinct challenge requiring tailored statutory design, these frameworks suggest structural principles for enabling regulatory closure without assuming complete remediation.