CAS Registry Number Application and Verification Services

Choose the Right CAS Registry Number Service Route

A CAS RN is a unique identifier assigned to a specific substance in CAS REGISTRY. However, a CAS RN does not by itself confirm chemical inventory listing, registration, approval, or permission for a particular market use. The appropriate route depends on whether the substance is already known, whether the available identity information is consistent, and how the result will be used.

Who Needs CAS RN Verification or Application Support?

This service is primarily intended for chemical manufacturers, exporters, importers, formulators, R&D teams, regulatory affairs teams, and supply chain compliance teams that need to establish or confirm substance identity.

• Companies developing or commercializing a new, proprietary, patented, or pre-commercial substance;

• Teams preparing an EU REACH, U.S. TSCA, China New Chemical Substance Registration, K-REACH, Japan CSCL/ISHL, or other regulatory submission;

• Companies receiving inconsistent CAS numbers, substance names, synonyms, or identity information from suppliers or third-party databases;

• Companies preparing SDSs, labels, customs documents, technical dossiers, or chemical inventory checks;

• Businesses handling polymers, UVCBs, reaction products, extracts, enzymes, proteins, industrial process products, or other complex substances;

• Teams unsure whether a commercial material should be assessed as one distinct substance or by its individual components.

Substance Types and Identity Scenarios We Support

CAS REGISTRY covers organic and inorganic compounds, metals and alloys, minerals, coordination compounds, organometallics, elements, isotopes, proteins, nucleic acids, polymers, and UVCBs. The information needed for a search or application depends on how clearly the substance can be defined.

Commercial mixtures and trade products require careful assessment. Ordinary formulated mixtures are generally assessed by their individual components, while some polymers, UVCBs, reaction products, extracts, or industrial process products may qualify as distinct substances. Broad categories, undefined trade products, finished formulations, living organisms, and insufficiently described materials may not be suitable for CAS RN assignment.

Information to Prepare for CAS RN Search or Application

Companies should provide as much consistent substance identity information as possible. Incomplete or conflicting data may lead to a mismatched result, an unsuitable service route, supplementary questions, or additional processing time.

Additional Project Information

• Existing CAS RNs or substance names provided by suppliers;

• Trade names, synonyms, internal codes, and available supporting documents;

• The intended use of the CAS RN or CA Index Name;

• The target market or regulatory framework;

• Any confidentiality requirements that should be assessed before submission.

REACH24H CAS RN Service Process

Timeline and Cost Factors

Lookup and assignment requests have different timelines. CAS currently states that a simple Registry Lookup for a matching chemical name or CAS RN is generally returned within 24 hours, excluding weekends and holidays. CAS also states that substance information and CAS RN assignment requests are processed within 10 working days after all required information has been received. REACH24H's project timeline may also include identity review, data gap resolution, technical preparation, and follow-up.

The overall timeline and cost may be affected by:

• Whether the substance already has a matching CAS REGISTRY record;

• The selected route, including lookup, verification, CA Index Name confirmation, CAS RN assignment, or IES;

• The complexity of the substance, especially polymers, UVCBs, extracts, enzymes, reaction products, and industrial process products;

• The completeness and consistency of the available identity information;

• Supplementary information or clarification requested during review;

• Confidentiality considerations and the intended regulatory use of the result;

• Any downstream compliance review required after the result is received.

A case-specific assessment is therefore required before a practical project estimate can be provided. Official CAS fees and processing information should also be confirmed at the time of the request through CAS Registry Services.

Confidentiality and Publication Considerations

Confidentiality should be assessed before a CAS request is submitted, especially for novel, proprietary, patented, or pre-commercial substances. CAS states that request processing is confidential. However, the assignment of a new CAS RN makes the substance identity publicly available in CAS REGISTRY; companies seeking to maintain substance identity confidentiality may need to consider a CA Index Name-only request instead.

Companies should also review how CAS information will be used in public documents, product databases, commercial platforms, SDSs, supplier communications, or regulatory submissions. CAS indicates that licensing may be required when CAS Registry Numbers are published to the public or used to support a publicly or commercially available platform. REACH24H can help clarify the intended use and identify questions that should be resolved before submission.

How REACH24H Can Help

REACH24H supports CAS RN projects as part of broader chemical identity and regulatory compliance work. Our services may include:

• CAS RN search and verification: Review known identifiers, names, structures, and supplier information to assess whether an existing CAS RN is likely to match the intended substance.

• Application route assessment: Help determine whether the project is best addressed through Registry Lookup, CAS Registry Services consultation, CA Index Name confirmation, IES, or another suitable route.

• Substance identity and data gap review: Assess structural, compositional, process-related, source-related, and analytical information before submission.

• Technical information preparation: Organize supporting information for well-defined substances, polymers, UVCBs, reaction products, extracts, industrial process products, and biotechnological substances.

• Communication and follow-up support: Assist with the selected request process and clarification of supplementary information where needed.

• Regulatory-use alignment: Review how the final CAS RN or CA Index Name should be used in SDSs, inventory checks, customs documents, and registration dossiers.

Why Choose REACH24H?

Frequently Asked Questions

Recommended Reading

• EU REACH Registration and Compliance Services

• China New Chemical Substance Registration under MEE Order No. 12

• U.S. TSCA Compliance Services for Existing and New Chemicals

• K-REACH Registration and Compliance Services

• Global GHS, SDS/MSDS and Label Compliance

Official Resources

• CAS REGISTRY

• CAS Registry Services

• CAS Registry Lookup Service

• CAS Common Chemistry

• CAS RN Verified Partner Program