Source-linked. Limits explicit.

Monthly US Bureau of Labor Statistics PPI observations are downloaded from its public API. Definitions are cross-checked with FRED. Month-over-month and year-over-year rates are calculated from reported index values, not from rounded percent changes. Values can be preliminary and revised. No commercial price database is scraped.

The pipeline stops on malformed, missing, non-finite, duplicate or older-than-120-day index data. Offline mode is explicit and retains original retrieval metadata. Government notices are filtered by publication date and title/abstract; relevance still needs human review.

FRED definitions are cited, but observations are fetched directly from BLS. Commercial competitors are linked only; their assessments, articles and databases are not redistributed. Public access does not by itself grant rights to republish all linked material.

1. BLS public API documentation
2. FRED ferrous scrap PPI definition
3. FRED nonferrous scrap PPI definition
4. USGS Copper 2026
5. Federal Register API documentation
6. FRED: Scrap PPI units and frequency
7. FRED: Nonferrous scrap PPI, BLS source
8. USGS Mineral Commodity Summaries 2026 — Copper
9. Argus Metals Newsletter: complimentary Scrap Markets coverage (search result verified; direct fetch blocked)
10. iScrap newsletter choices
11. ScrapMonster membership plans and billing terms