As of July 2025, California’s Low Carbon Fuel Standard requires renewable fuel producers using specified source feedstocks to secure attestation letters reaching back to the point of origin. This marks a significant shift in compliance expectations, creating new challenges for producers to document and verify every step of their supply chain. What is a specified source feedstock?Under California’s LCFS, specified source feedstocks (SSFS) are byproduct fats, oils and greases from commercial or industrial processes. Examples include:• Used cooking oil • Animal fats and fish oil • Distiller’s corn or sorghum oil • Yellow or brown grease &nbsp;These feedstocks are used in pathways for biodiesel, renewable diesel, alternative jet fuel and coprocessed refinery products. SSFS pathways can qualify for a reduced carbon intensity (CI) score, making them especially valuable for producers seeking to maximize LCFS credit generation. But with this benefit comes stricter oversight, producers must now provide evidence of chain of custody from the point of origin through delivery to the fuel production facility. The requirement in detailUnder the amended LCFS, each entity in the SSFS supply chain must now maintain a supplier attestation letter. &nbsp;Covered entities include points of origin, collectors, aggregators, traders, distributors and storage facilities involved from the feedstock’s origin through delivery to the fuel producer. &nbsp;The attestation letter must: 1. Confirm feedstock integrity• No additional processing (such as drying or cleanup) beyond what is explicitly included in the pathway life cycle analysis and carbon intensity (CI).2. Verify truth and accuracy• Feedstocks meet the definitions approved by the Executive Officer during fuel pathway validation and certification. • Deliveries match feedstock transfer documents and are not mixed with other materials. • Feedstocks were not intentionally produced, modified or contaminated to meet the definition of an SSFS.3. Meet strict documentation standards• On company letterhead. • Separate letter for each specified source feedstock. • Signed by an authorized representative of the supplier. • Maintained by the supplier and submitted electronically upon request by a CARB accredited verifier, verification body or the Executive Officer.Looking ahead, starting with the 2026 data year for all pathway reports, crop-based feedstocks will also require attestations from the point of origin through the first gathering point, including submission of farm level geographical shapefiles or coordinates—an added step that will demand both time and resources. CARB guidance still developingAlthough the SSFS requirement is already in effect, the California Air Resources Board is still developing implementation guidance. Key questions remain unanswered, particularly: what happens if a producer cannot obtain 100% of the required attestations?It is not yet clear whether missing attestations will trigger a qualified positive statement through third-party verification, or more severe consequences. While it seems unlikely CARB will immediately classify such situations as adverse verification statements, the risk remains until guidance is finalized. Why this matters for producersThe new SSFS attestation rule elevates compliance standards and places greater accountability across the feedstock supply chain. For renewable fuel producers, the implications are serious:• More intensive documentation and tracking, especially from the point of origin. • Heightened supply chain risks, since producers depend on upstream partners to provide accurate attestations. • Potential loss of reduced CI scores if attestations or chain of custody evidence are incomplete or missing—directly impacting LCFS credit generation and the economic viability of pathways that rely on SSFS.The value of SSFS in delivering lower CI credits makes compliance especially critical. Producers unable to demonstrate an unbroken chain of custody risk losing not just compliance standing, but also the financial advantages of their pathways. Steps producers should take nowWith the SSFS attestation requirement already in effect, producers should act quickly to strengthen compliance. Recommended steps include:• Review supplier relationships to ensure partners can provide compliant attestation letters. • Develop internal protocols for collecting, reviewing and storing attestations. • Plan for 2026 required attestations for crop-based feedstocks, including geographical data collection. • Engage verification bodies early to understand how attestations will be reviewed. • Communicate with suppliers now about expectations and deadlines to avoid disruptions.The ability to maintain reduced CI scores will ultimately depend on how quickly producers adapt their systems to meet these new chain of custody and attestation requirements. The bottom lineCalifornia’s new SSFS attestation requirement is a gamechanger for renewable fuel producers. While CARB has yet to finalize implementation guidance, the rule is in effect now—and the consequences for noncompliance could be significant. Producers who act quickly to update compliance systems, strengthen supplier communication and prepare for audits will be best positioned to maintain eligibility for LCFS credits and avoid costly setbacks.Author: Danielle Anderson Senior Government Policy and Advocacy Manager Christianson PLLP 320.441.6482 danderson@christiansoncpa.com

2025-08-13 - California’s new specified source feedstock attestation requirement: A critical new compliance step for renewable fuel producers (3 publications)

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As of July 2025, California’s SCFS requires renewable fuel producers using specified source feedstocks to secure attestation letters reaching back to the point of origin. This marks a significant shift in compliance expectations.

California’s new specified source feedstock attestation requirement: A critical new compliance step for renewable fuel producers

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