If you sell anything with a lithium battery on Amazon, you have either already lived through the hazmat compliance process or you are about to. For Voro Motors — electric scooters, all lithium-powered — this was not an edge case. It was the operational reality for every SKU in the catalog.
Amazon's hazmat program is technically well-documented in Seller Central. In practice, the documentation assumes you already understand the process and the timelines. This is the version that explains what actually happens, what to prepare, and how to maintain operational continuity while Amazon reviews your products.
Before you list
The Safety Data Sheet (SDS) is the foundational document for any hazmat listing. For lithium battery products, Amazon requires an SDS that meets specific format standards — the document needs to include section headers in a prescribed order, cover all required hazard categories, and be issued by the manufacturer or a qualified safety consultant. Consumer product SDS documents and industrial SDS documents are different formats; Amazon generally requires the industrial UN 38.3 test summary format for lithium batteries.
Get the SDS before the listing is live. This sounds obvious. It is not the practice. Many brands list first and submit SDS documentation after the fact when Amazon flags the product. That sequence means your product can be pulled from FBA mid-inbound, creating an OOS event while you scramble for paperwork that should have existed before shipment one.
The SDS submission process goes through Seller Central's hazmat review portal. Submit via the product's ASIN detail page under the "dangerous goods" section. Include the SDS in PDF format. Amazon's review team processes the submission and either approves the hazmat classification, requests additional documentation, or denies the listing. There is no customer service number to call to check status — the case system is the only communication channel.
The 45-day cap
Once approved as a hazmat product, Amazon imposes a maximum days-of-supply limit for FBA inventory. For most hazmat categories, that cap is 45 days of supply. You cannot hold more than 45 days of projected demand in FBA at any given time.
For a product selling 10 units per day, 45 days of supply is 450 units. For a product selling 100 units per day, it is 4,500 units. The cap is percentage-based, not absolute. But it is also not negotiable in the way that standard supply limits are — hazmat caps come from Amazon's storage compliance requirements, not from sales velocity algorithms, so case filings for limit increases work differently and are less reliable.
The operational implication is that hazmat products require 3PL buffer stock as a structural element of the inventory strategy, not a contingency. You will always be limited in how much you can hold in FBA. Plan for the flow of inventory from 3PL to FBA rather than trying to pre-position everything in FBA before peak demand.
The review timeline problem
Here is where things get genuinely disruptive. When Amazon initiates a hazmat review on an existing listing — which can happen when you update product information, change packaging, or Amazon's compliance team flags the product independently — the ASIN can be pulled from FBA sales and receive while the review is pending.
Review timelines are not fixed. For straightforward SDS submissions with clean documentation, approval can happen in 5 to 10 business days. For complex products or cases where Amazon requests additional documentation, the review can run three to four weeks. During that window, the product may be unsaleable on Amazon and unable to receive new FBA inventory.
The operational response is the 3PL buffer. For any hazmat SKU, maintain a minimum of 30 days of demand in 3PL at all times. This is not safety stock in the traditional sense — it is the inventory you will need to have ready to send into FBA the day the review clears and the receive block lifts. If you are sitting at zero 3PL inventory when the review ends, you have a minimum five-day transit window before FBA is restocked. That is five days of OOS on a product that was already suppressed during the review.
What to do when a review blocks your PO
The review blocking a purchase order is the worst timing scenario. You have inventory that needs to ship from your supplier, but Amazon will not receive hazmat products under active review. Your options are limited but not zero.
First, check whether FBM (Fulfillment by Merchant) is available for the ASIN. If the listing is still live but FBA receive is blocked, you can continue selling via FBM while the review processes. This requires having the product at a location you can ship from, which is another argument for maintaining 3PL buffer stock. FBM at the same price as FBA will reduce conversion rate — customers prefer Prime — but it keeps the listing active and generates sales data rather than a BSR crater.
Second, file a case in Seller Central with the complete SDS and any supporting UN 38.3 test documentation. Include a note in the case documenting the business impact — units of lost daily sales, estimated FBA revenue at risk, current 3PL inventory waiting to ship. Amazon's compliance team has some discretion on review prioritization. Giving them complete documentation in the first submission prevents a back-and-forth that adds another week to the timeline.
Third, do not re-submit the PO to an alternate supplier or create a new variation listing to work around the review. Amazon's compliance team will catch this, and the outcome is worse than the original review.
The summary
Prepare the SDS before the first listing goes live. Keep it current every time the product changes. Maintain 30-plus days of 3PL buffer stock for every hazmat SKU as a permanent operational requirement, not a reaction to problems. File cases immediately when reviews open, with complete documentation included on the first submission. If FBM is viable during a review window, activate it.
The brands that lose the most to hazmat compliance issues are the ones that treat SDS preparation and 3PL buffering as optional until something goes wrong. For lithium battery products, something will go wrong. The only question is whether you have the infrastructure in place to absorb it.
