Project 2025 Tracker / What’s done, what’s next

13. Environmental Protection Agency · Notable

Reject the low-dose linear non-threshold model and precautionary defaults

Partially done

438 13. Environmental Protection Agency

“Reject precautionary default models and uncertainty factors. … EPA’s heavy reliance on default assumptions like its low-dose, linear non-threshold model bake orders of magnitude of risk into key regulatory inputs and drive flawed and opaque decisions. … EPA should implement an approach that defaults to less restrictive regulatory outcomes.”

What has happened

  1. Partially done

    Executive Order 14303 §4(e) states the rule the Quote's first sentence asks for: employees “shall be transparent about the likelihood of the assumptions and scenarios used”, and “highly unlikely and overly precautionary assumptions and scenarios should only be relied upon in agency decision-making where required by law or otherwise pertinent to the agency's action.” Sections 4(c) and 4(f) add documented uncertainty propagation and a “weight of scientific evidence” approach. That is the precautionary-defaults half. The low-dose linear non-threshold model, which the Quote names, is untouched: the order contains no dose-response passage, and a Federal Register full-text search of EPA documents for “linear no-threshold” returns nothing in the window. Nor has EPA adopted the Quote's closing instruction to default to less restrictive regulatory outcomes.

Research log

What was searched, and what didn’t count as evidence

Research notes

  • The TSCA risk-evaluation procedures proposal (2025-09-23) is the EPA rulemaking closest to the Quote’s subject — it reopens the 2024 amendments to the framework rule that governs how EPA handles uncertainty in existing-chemical risk evaluations, and it invokes EO 14303. It is a proposal, so it carries the partial rather than lifting it.
  • The linear non-threshold half is the same object as #1100 (Reassess the Linear Non-Threshold radiation standard), which an earlier search left at not started after a Federal Register search for “linear no-threshold” restricted to EPA returned count 0. Nothing found since changes that.
  • Two-object ask, one object delivered by a binding government-wide directive → partial, since a two-object ask with one object delivered is partial.
Action
eliminate
Object
precautionary default models and the low-dose linear non-threshold model
ID
1169