Tetrahydrofuran (THF; CAS 109-99-9; C4H8O; molecular mass 72.11 g/mol) is a cyclic aliphatic ether with a closed-cup flash point of -14 °C, a boiling range of 65–66 °C at 101.3 kPa, and a vapour pressure of 19.3 kPa at 20 °C. Under CLP (EC) No 1272/2008, the classification applied to THF commonly includes Flam. Liq. 2 H225, Acute Tox. 4 H302, Eye Irrit. 2 H319, STOT SE 3 H335, and Carc. 2 H351; the transport classification is UN 2056, Class 3, Packing Group II. The label requires the signal word Danger and, where the classification includes H351, the GHS08 health hazard pictogram alongside GHS02 and GHS07.

The regulatory question expressed as THF OEM & Private Label: Who Owns the Label, the SDS & the Liability is not a marketing distinction. It is a compliance status determination that assigns supplier duties under 29 CFR 1910.1200(g), REACH Article 31, and CLP Article 17. In an OEM/private-label arrangement, the entity whose name appears on the label is normally the supplier for downstream hazard communication purposes unless the product is shipped in the OEM’s name. The SDS and label must be consistent with that identity, the package, and the stabilised condition of the delivered liquid.

Does a Private-Label Repackager Inherit the SDS Authoring Obligation for THF?

Under 29 CFR 1910.1200(g), chemical manufacturers and importers are required to author or obtain a safety data sheet for each hazardous chemical. A private-label distributor that receives sealed THF containers, applies a different label, and ships without opening the container does not automatically become a chemical manufacturer under the HazCom definition. However, if the private-label entity is the responsible party named in SDS Section 1.3, downstream users will hold that entity responsible for the accuracy of the full sixteen-section document. If the product is repackaged into different container sizes, the repackager must ensure that the label and SDS remain accurate for the delivered article, including the container material, closure system, headspace oxygen environment, and stabiliser content.

Under REACH Article 31 and Annex II as amended by Commission Regulation (EU) 2020/878, SDS Section 1.3 must identify the supplier placing the substance on the market. When THF is sold under a private label, the label owner is that supplier. The OEM manufacturer may still be identified in Section 1.1 as the product source, but the private-label entity is not exempt from transmitting classification data or maintaining a coherent technical dossier. In many toll blending contracts, the OEM provides classification data and the private-label supplier authors the customer-facing SDS. Liability for failure to warn may then attach to both parties: the OEM for process-derived hazard information and the private-label supplier for label accuracy at the point of sale. Published regulatory guidance specific to private-label THF is limited; therefore the role assignment must follow general chemical distributor and supplier obligations under OSHA HCS 2012, REACH, and CLP.

Peroxide Control and BHT Inhibitor Verification in Contract-Filled THF

THF is a peroxide-forming ether when exposed to atmospheric oxygen. The standard stabilisation practice is addition of 2,6-di-tert-butyl-4-methylphenol (BHT; CAS 128-37-0) at 100–300 mg/kg. Uninhibited THF, or THF with depleted BHT, can accumulate tetrahydrofuran peroxide species that create a deflagration risk during distillation or evaporation. In an OEM/private-label split-fill operation, the OEM often supplies a nitrogen-blanketed 200-L mild-steel or 316L stainless steel drum. The private-label packager transfers product through a 0.45 µm PTFE membrane into 1-L amber borosilicate glass bottles under dry nitrogen. The SDS must disclose the stabiliser identity in Section 3.2 and the storage temperature limit in Section 7. A private-label SDS stating only “BHT inhibited” without a concentration range is technically incomplete because BHT depletion below 100 mg/kg changes the product hazard profile.

Batch-to-batch verification requires gas chromatographic or HPLC determination of BHT, and peroxide checks by iodometric titration or calibrated test strips. Many plant specifications set an incoming peroxide limit of 50 mg/kg as hydrogen peroxide equivalents. Storage at temperatures above 30 °C or repeated opening of the bottle accelerates BHT consumption and peroxide formation. The hazard communication consequence is that the SDS Section 2 flammability classification may remain valid while the practical storage hazard increases; the private-label supplier therefore carries a disclosure burden that exceeds a simple GHS label.

For THF shipped as a split-fill from a 200-L drum into 1-L borosilicate glass bottles under a private label, the label owner inherits packaging-related failure modes even when the liquid itself was produced by the OEM. The vapour pressure of 19.3 kPa at 20 °C makes headspace oxygen and closure permeation operationally significant. Low-density polyethylene cap liners soften or swell in THF over extended contact; PTFE-lined closures are used to maintain seal integrity and prevent loss of inhibitor. If a private-label supplier substitutes a generic polypropylene closure with an unlined face, solvent vapour can escape during transport and create a flammable atmosphere inside the outer fibreboard packaging. Under 49 CFR Part 173 and ADR Chapter 3.2, a Class 3, Packing Group II liquid must be packed in closures that withstand the vapour pressure at 55 °C without leaking. Failure to meet that packaging performance standard is a regulatory violation independent of SDS accuracy. Product liability litigation may examine whether the private-label supplier’s packaging specification matched the SDS Section 7 storage and handling instructions. Published data for closure material compatibility in private-label THF bottle filling is limited; industrial practice relies on closure supplier compatibility testing rather than a single ASTM method.

SDS Section 1.3 Supplier Identity and Toll Blending Liability

Section 1.3 of a REACH-compliant SDS and the responsible-party field of an OSHA-compliant SDS determine the regulatory recipient for downstream hazard information requests. In a toll blending arrangement, the OEM distillation plant may produce THF with a specified BHT concentration and water content, but the private-label brand owner may be the only name on the material label. Under CLP Article 17, the label must include the supplier’s name, address, and telephone number; under 29 CFR 1910.1200(f)(1), the responsible party must be shown. When the OEM name is absent, the private-label entity assumes the visible supplier duty. If a downstream pharmaceutical company requests extended safety data on peroxide formation, the private-label supplier must either maintain the technical dossier or have a contractual right to obtain it from the OEM.

The SDS must also be consistent with the label. A private-label THF label that omits the H351 suspected carcinogen statement, or that omits the BHT inhibitor declaration, creates a misbranding risk even if the OEM’s master SDS contains the correct classification. Under REACH Article 31(9), the supplier must update the SDS within 3 months of becoming aware of significant new hazard information. In a private-label arrangement, if the OEM changes BHT concentration from 200 mg/kg to 100 mg/kg, the label owner must transmit the revised SDS to customers within that interval. Failure to do so transfers liability from the OEM’s process change to the private-label supply chain.

In high-purity THF used for lithium-ion battery separator coating or pharmaceutical peptide synthesis, private-label supply adds specification risk that SDS hazard statements alone do not resolve. For pharmaceutical applications, THF is a Class 2 residual solvent under ICH Q3C with a permitted daily exposure of 7.2 mg/day and a concentration limit of 720 ppm in drug substances when the solvent is not removed. A private-label supplier that repackages THF under air instead of nitrogen may not detect antioxidant depletion unless the buyer’s incoming QC includes a peroxide titration. The OEM certificate of analysis may show water by Karl Fischer titration below 0.005 wt% and BHT at 180 mg/kg, but if the private-label repackager uses bottles that are not pre-dried at a relative humidity below 30%, water content can increase beyond the buyer’s limit. Failure of the final article in a process, such as hazy PVDF dope or poor layer adhesion in a battery separator, is often traced to packaging and storage rather than to the original THF chemistry. Published data for this specific configuration is limited; therefore the SDS must be treated as a hazard communication floor, not as a substitute for process-specific CoA limits, packaging inertization records, and peroxide retest intervals.