40 CFR 1506.6

Not found in the current CFR. No part 1506 exists under title 40 in the eCFR as of 2026-08-23. That means either the part was removed or renumbered, or the citation in the publication is wrong. Either way, verify before relying on it — this is exactly the kind of stale reference worth catching.

What happened to it — verified: This was Council on Environmental Quality NEPA implementing regulations (40 CFR 1500-1508). Repealed effective 11 Apr 2025 (CEQ interim final rule of 25 Feb 2025, adopted as final effective 8 Jan 2026): CEQ concluded it lacked rulemaking authority after E.O. 14154 rescinded E.O. 11991. What to look to now: The NEPA statute itself plus each agency's own NEPA procedures — there is no longer a government-wide NEPA regulation to cite. [Federal Register]

Citation counts come from the publication text, not from a summary. A high count is frequency, not legal weight — open the pub and read the citation in context.