Demurrage & Detention Invoice Dispute

The situation

A small importer gets hit with a $4,500 detention invoice from an ocean carrier during a period of port congestion. They have no idea whether the invoice actually meets FMC's required content checklist or was sent within the 30-day deadline, and if it wasn't, federal rules say they legally owe nothing at all. They also have a 30-day window to request fee mitigation, but no idea how to build that case, while FMC is already investigating over 100 similar shipper complaints in the background.

Who receives this

Small importers, retailers, manufacturers, and distributors that ship goods via ocean freight and receive a detention or demurrage invoice from an ocean carrier, NVOCC, or marine terminal operator.

Why the agency will not advise you

FMC created these shipper-protective rules but doesn't help an individual billed importer check whether their specific invoice complies or build a dispute; the only content found is general educational guides, not a tool that evaluates a specific invoice or drafts a specific request.

Key facts, with sources

• FMC's Demurrage and Detention Billing Requirements rule took effect May 28, 2024 under the Ocean Shipping Reform Act of 2022. Section 541.6 sets out five categories of required invoice content comprising up to 20 numbered items depending on whether the shipment is an import or export (container number, dates used to calculate free time, applicable rate, billing/billed party identification, and more), failing to include any applicable required minimum information eliminates the billed party's obligation to pay the applicable charge. Common carriers and marine terminal operators must issue detention and demurrage invoices within 30 calendar days from when charges were last incurred; NVOCCs get an additional 30 calendar days. On September 23, 2025, the D.C. Circuit Court of Appeals upheld the rule's core provisions, setting aside only the narrower section governing who may be billed. Source: FMC Publishes Final Rule on Detention and Demurrage Billing Practices — Federal Maritime Commission · U.S. Court of Appeals Issues Decision in Case on Demurrage and Detention Billing Practices — Federal Maritime Commission
• Billed parties (importers/shippers) have at least 30 calendar days to make fee mitigation, refund, or waiver requests, and if a timely request is made, the billing party must attempt to resolve the matter within 30 calendar days unless both parties agree to a longer timeframe. FMC is currently investigating over 100 charge complaints where shippers allege ocean carriers placed unjust detention/demurrage fees on them, confirming this is an actively contested, live enforcement environment. No self-serve invoice-compliance-checker or dispute-builder tool was found in two dedicated searches; available resources (Tradlinx's dispute guides, unicargo's 2026 importer playbook, Mallory Group's explainer content) are educational, not tools that evaluate a specific invoice or draft a specific dispute request. Source: FMC wants ocean carriers to prove detention, demurrage charges comply with OSRA — Supply Chain Dive · eCFR :: 46 CFR Part 541 -- Demurrage and Detention

When to bring in a professional

Self-serve responses fit routine cases: clear facts, amounts a business can absorb, and a deadline still ahead of you. Bring in a licensed professional when the amount at stake is large relative to their fee, the facts are genuinely disputed, criminal exposure is possible, or the deadline has already passed. A short paid consultation to sanity-check your plan is often worth it even when you handle the filing yourself.

All sources for this guide

1. FMC Publishes Final Rule on Detention and Demurrage Billing Practices — Federal Maritime Commission
2. U.S. Court of Appeals Issues Decision in Case on Demurrage and Detention Billing Practices — Federal Maritime Commission
3. FMC wants ocean carriers to prove detention, demurrage charges comply with OSRA — Supply Chain Dive
4. eCFR :: 46 CFR Part 541 -- Demurrage and Detention