Prepared admixtures containing chemical substances not listed on the TSCA Chemical Substance Inventory may require pre-manufacture notification before import. Importers must certify TSCA compliance or non-applicability at entry; formulations containing novel polymers or surfactants warrant particular scrutiny. A licensed customs broker or TSCA consultant should review the product's Safety Data Sheet against the TSCA inventory prior to shipment.

Accelerators shorten concrete set time and are used in cold-weather pours or rapid-turnaround precast production, while retarders extend workability for large pours or hot-weather conditions. Although both fall within this SITC heading, importers and buyers should specify the admixture type in purchase contracts and technical data sheets, as substitution between types can cause significant structural performance issues.