A Nationally Recognized Testing Laboratory (NRTL) is a private sector organization recognized by the United StatesOccupational Safety and Health Administration (OSHA) to test and certify certain products—primarily electrical equipment and materials—for compliance with applicable safety standards, ensuring safe use in workplaces under OSHA's jurisdiction.[1]The NRTL Program was established in 1988 through the promulgation of 29 CFR 1910.7, which defines the requirements for recognition and authorizes OSHA to leverage qualified independent laboratories to perform third-party testing and certification in lieu of federal government testing.[2] This initiative stemmed from a 1983 federal court ruling that directed OSHA to expand its recognition beyond specific laboratories like Underwriters Laboratories (UL) and Factory Mutual (FM) to include other capable third-party entities, promoting broader access to safety certification services.[3] The program's primary goal is to protect workers from hazards associated with unsafe products by verifying conformance to consensus-based test standards, such as those from UL, ANSI, and IEEE, through rigorous evaluation, factory inspections, and ongoing follow-up services.[4]To qualify for NRTL status, an organization must demonstrate capabilities in areas including test equipmentcalibration, qualified personnel, a robust quality control program, independent product evaluation methods, and the ability to authorize use of its registered certification mark on compliant products; OSHA evaluates applications against these criteria in Appendix A to 29 CFR 1910.7 and assigns each NRTL a specific scope of recognized test standards.[2] As of 2025, OSHA recognizes 22 NRTLs, operating more than 60 testing sites across the United States and internationally, covering 39 categories of products that require certification for workplace use, including items like circuit breakers, weldingequipment, and hazardous location fixtures.[5] These laboratories play a critical role in OSHA enforcement, as employers must ensure that electrical and certain other equipment in construction, generalindustry, and maritime settings bears an NRTL mark to comply with standards like 29 CFR 1910.303.[4]
Overview
Definition and Purpose
A Nationally Recognized Testing Laboratory (NRTL) is defined as an independent third-party organization that has been recognized by the Occupational Safety and Health Administration (OSHA) to test and certify specific categories of products, ensuring they meet safety standards for use in U.S. workplaces.[6] These laboratories operate outside of federal government control but must demonstrate technical expertise, independence, and adherence to rigorous criteria to qualify for recognition.[1] By performing evaluations against consensus-based standards, NRTLs help verify that equipment poses minimal risk to workers, focusing on hazards like electrical shock, fire, or explosion.[4]The primary purpose of the NRTL program is to leverage private sector capabilities for product safetycertification, alleviating the direct testing responsibilities that would otherwise fall to OSHA and thereby reducing governmental administrative burdens while preserving high standards of occupational safety.[7] Established under OSHA's regulatory framework, the program ensures that certified products comply with workplace safety mandates without compromising enforcement efficacy.[1] This approach covers a range of equipment, including electrical devices, fire protection systems, and apparatus designed for hazardous locations, allowing manufacturers to obtain approvals that facilitate market access and regulatory compliance.[8]Central to the NRTL function is the issuance of certification marks—unique identifiers such as the UL mark—that signify a product's successful testing and approval, enabling employers to rely on these marks as evidence of OSHA compliance without requiring further independent verification.[4] These marks must be affixed to the product or its packaging, and NRTLs maintain ongoing surveillance to ensure continued conformity, reinforcing trust in the certification process across industries.[9]
Legal Basis
The Nationally Recognized Testing Laboratory (NRTL) program derives its statutory authority from the Occupational Safety and Health Act of 1970 (OSH Act), 29 U.S.C. §§ 651 et seq., which established the Occupational Safety and Health Administration (OSHA) to ensure safe and healthful working conditions. Specifically, Section 6(b) of the OSH Act grants the Secretary of Labor the power to promulgate, modify, or revoke occupational safety and health standards through rulemaking procedures, including the recognition of qualified private organizations to perform testing and certification functions that support compliance with these standards.[10]The primary regulatory framework for the NRTL program is codified in 29 CFR 1910.7, which defines an NRTL as an organization recognized by OSHA to test and certify certain equipment and materials for workplace safety. This regulation specifies the criteria for recognition, such as the capability to conduct appropriate tests, maintain independence, and ensure credible results, as well as the administrative processes for granting, expanding, or revoking recognition. Appendix A to 29 CFR 1910.7 further details OSHA's evaluation procedures for applicants, emphasizing the program's role in facilitating third-party certification to meet federalsafety requirements.[6]The NRTL program integrates with broader OSH Act provisions, including the general duty clause in Section 5(a)(1), which mandates that employers furnish employment and a place of employment free from recognized hazards likely to cause death or serious harm. This clause underscores the need for certified equipment to mitigate risks in workplaces. Furthermore, specific OSHA standards reference NRTL approvals, such as 29 CFR 1910.303(a), which requires electrical equipment to be approved as defined in 29 CFR 1910.399 (including, where applicable, listing or labeling by an NRTL in accordance with nationally recognized testing standards) to ensure safe installation and use.[11][12]
History
Establishment
The Nationally Recognized Testing Laboratory (NRTL) program originated from legal challenges to the Occupational Safety and Health Administration's (OSHA) informal reliance on private testing organizations for certifying workplace equipment safety. In 1982, MET Electrical Testing Company filed a lawsuit (No. Y-82-1133, D. Md.) against the Department of Labor, alleging that OSHA's specific references to Underwriters Laboratories Inc. (UL) and Factory Mutual Research Corporation (FMRC) in 23 standards under 29 CFR Part 1910 violated due process and antitrust laws by favoring those entities without a formal recognition process.[13] This suit was settled in 1983, with OSHA agreeing to remove the UL and FMRC references and establish procedures for recognizing qualified testing laboratories to ensure fair competition and compliance with the Occupational Safety and Health (OSH) Act of 1970.[13]A subsequent enforcement action in 1987 (No. Y-87-1480, D. Md., filed December 8, 1987) by MET compelled OSHA to finalize the recognition process within 120 days, addressing ongoing delays in implementing the 1983 settlement and the practical need for third-party testing to fill gaps in federal capacity for evaluating electrical and other equipment safety.[13] In response, OSHA issued a final rule on April 12, 1988, formally establishing the NRTL program under 29 CFR 1910.7, which defined criteria for recognizing laboratories capable of testing and certifying products to applicable standards.[14] The rule took effect on June 13, 1988, granting temporary five-year recognition to UL and FMRC to maintain continuity in certification services while applications for permanent status were processed.[14]Initially, the program's scope was limited to the 23 OSHA standards provisions requiring third-party certification, primarily focused on electrical safety testing for workplace equipment, as authorized by section 6(b) of the OSH Act to promote safe working conditions without overburdening federal resources.[14] UL became the first laboratory formally recognized under the new program on June 13, 1988, marking the operational start of structured oversight for private testing entities. This establishment addressed the lawsuit's core concerns by creating an equitable, auditable framework for NRTLs to certify compliance, thereby enhancing worker protection through verified product safety.[14]
Development and Expansion
Following its establishment through the 1988 regulation, the NRTL program experienced steady early growth in the 1990s, with OSHA recognizing an increasing number of private sector laboratories to perform product testing and certification. By late 1994, the program had expanded to accredit 12 laboratories, enabling broader coverage of workplacesafety equipment approvals.[15] This period also saw clarifications in recognition procedures, as outlined in a 1994 Federal Register notice, alongside the inclusion of additional product categories such as automatic fire detection devices and equipment under the program's scope.[16][8]In 2000, OSHA introduced a formal fee structure to support the program's administrative and operational needs, amending 29 CFR 1910.7 by adding paragraph (f) to cover costs for processing applications, conducting assessments, and performing audits.[17] This measure helped sustain expansion efforts as the demand for certified products grew. During the 2010s, the program further developed by recognizing more international laboratories, including those based in Canada and Europe, which enhanced global access to NRTL services for U.S. workplacecompliance.[5]Key policy advancements continued into the late 2010s, with OSHA issuing Directive CPL 01-00-004 on October 1, 2019, which updated and streamlined application procedures, clarified evaluation criteria, and improved guidelines for NRTL operations to facilitate efficient growth.[9] Recent expansions include the recognition of LabTest Certification Inc. in 2021, adding capabilities for testing electrical and other safety-related products.[18] As of 2025, the program supports 22 active NRTLs, reflecting its evolution into a robust framework for third-party certification.[5]
Recognition Process
Application Requirements
To apply for recognition as a Nationally Recognized Testing Laboratory (NRTL) under OSHA's program, an organization must first meet specific eligibility criteria outlined in the regulations. The applicant must be completely independent from manufacturers, vendors, or employers whose products it tests, ensuring no financial or organizational ties that could compromise objectivity, as required by 29 CFR 1910.7(b)(3). Additionally, the organization needs adequate resources, including properly equipped facilities, trained personnel, and established procedures for testing and quality control to demonstrate capability in safety testing and certification, per 29 CFR 1910.7(b)(1) and (b)(2). Applicants must show competence in at least one product category by providing evidence of testing capabilities aligned with applicable standards, tying into the broader recognition criteria in 29 CFR 1910.7.[6]The application requires submission of comprehensive documentation to verify compliance. This includes an organizational chart detailing the structure, ownership, and key personnel involved in NRTL operations; a quality manual describing testing, certification, and quality assurance procedures; and a list of proposed test standards for the requested scope, such as ANSI or ASTM standards appropriate for the product categories. Supporting evidence must also cover accreditation or equivalent demonstrations of competence, such as compliance with ISO/IEC 17025 for testing laboratories and ISO/IEC 17065 for certification bodies, along with resumes of key staff, testing procedures, calibration programs, and registration of any certification marks with the U.S. Patent and Trademark Office. All materials are submitted via OSHA's application form, available through the NRTL Program office.[7][9]Fees for the initial application process are structured to cover administrative and technical reviews, with amounts based on the 2019 revised schedule (current as of 2025). Applicants pay an initial administrative evaluation fee of approximately $4,160 for limited review, plus technical evaluation fees such as $8,320 for management procedures and $2,490 per test standard or site reviewed. On-site assessment costs, including auditor time at $830 per day plus travel, are billed separately after acceptance, bringing total initial fees to around $5,000–$10,000 depending on scope, with all payments required in advance via check or electronic transfer to OSHA. Annual fees apply post-recognition for ongoing audits.[6][19]
Evaluation and Renewal
The evaluation of applications for Nationally Recognized Testing Laboratory (NRTL) recognition begins with a desk review conducted by the Occupational Safety and Health Administration (OSHA), where staff assess the submitted application for completeness and initial compliance with the criteria outlined in 29 CFR 1910.7.[20] This step ensures that the applicant has provided sufficient documentation on its facilities, equipment, personnel qualifications, testing procedures, and quality control systems before proceeding to more intensive scrutiny.[20] Following the desk review, OSHA arranges an on-site assessment of the applicant's facilities, personnel, and operational procedures, typically performed by qualified experts using consensus-based standards or other relevant criteria to verify capability and competence.[20] The entire evaluation process, encompassing the desk review, on-site assessment, public comment period, and final decision, generally spans several months.[7]Upon successful completion of the evaluation, OSHA grants recognition through a notice published in the Federal Register, which specifies the scope of recognition, including the test standards and product categories the NRTL is authorized to cover.[20] Initial recognition is valid for a period of five years, during which the NRTL must adhere to the terms of its recognition and maintain compliance with 29 CFR 1910.7 requirements.[4] To support ongoing oversight, OSHA conducts periodic on-site audits of recognized NRTLs at least once every two years, though the frequency may vary as determined by the Director, to evaluate continued adherence to program standards, testing practices, and certification processes.[9]Renewal of NRTL recognition requires the submission of an updated application approximately nine to twelve months prior to the expiration of the current term, detailing any changes in facilities, procedures, or scope since the last recognition.[20] The renewal evaluation follows a similar process to initial recognition but may omit an on-site assessment if OSHA determines it unnecessary based on recent audits or other evidence of compliance; a preliminary notice is published in the Federal Register with a minimum 15-day public comment period before final approval.[20] Successful renewals extend recognition for another five years, provided the NRTL demonstrates ongoing compliance with evolving standards and program requirements.[4]In cases of non-compliance, such as failure to maintain adequate testing capabilities or adhere to quality assurance procedures, OSHA may initiate revocation proceedings, offering the NRTL a 60-day period to correct deficiencies and an opportunity for a hearing.[20] Since the program's inception in 1988, OSHA has revoked or accepted voluntary terminations from seven NRTLs, including instances due to acquisition by other organizations, denial of renewal, or expiration without reapplication.[21]
Recognized Laboratories
Current List
As of November 2025, the Occupational Safety and Health Administration (OSHA) recognizes 22 active Nationally Recognized Testing Laboratories (NRTLs), which are independent organizations authorized to test and certify certain equipment and materials to ensure compliance with applicable product safety standards.[5] These NRTLs operate from locations primarily in the United States (16), with additional sites in Canada (4), Japan (1), and Germany (1), facilitating certification services across North America and select international contexts.[5] All listed NRTLs maintain active status, with individual recognition histories documented in OSHA's public dockets, such as OSHA-2007-0039 for Intertek Testing Services NA, Inc.[5]The following table enumerates the current NRTLs, including their full names, acronyms where applicable, and primary locations:
This list represents the program's expansion to support diverse certification needs while upholding rigorous safety validation.[5]
Scope of Recognition
The scope of recognition for a Nationally Recognized Testing Laboratory (NRTL) defines the specific test standards and product categories for which the organization is authorized to perform safety testing and certification under OSHA's NRTL Program, ensuring compliance with workplacesafety regulations such as those in 29 CFR 1910.7.[4] This recognition is tailored to each NRTL's demonstrated capabilities, facilities, and expertise, limiting certifications to only those approved areas to maintain program integrity.[1]Variations in scope exist among NRTLs, with some offering broad coverage across multiple product categories, such as electrical safety equipment and hazardous locations, while others focus on specialized areas like fire protection systems. For instance, UL LLC holds recognition for 614 test standards, encompassing a wide range including UL 489 for molded-case circuit breakers in electrical safety and ISA 60079-11 for intrinsically safe equipment in hazardous locations.[22] In contrast, CSA Group is recognized for 298 standards, many involving Canadian-American joint standards (e.g., CSA/AM Z21.1 for household cooking gas appliances) that adapt U.S. requirements for cross-border compatibility.[23]FM Approvals LLC, specializing in fire and explosion prevention, covers 92 standards, such as FM 1311 for fire pumps and FM 3600 for electrical equipment in hazardous locations.[24] OSHA maintains a master list of over 600 appropriate test standards from which NRTL scopes are drawn, updated periodically to reflect current safety needs.[25]NRTL scopes can be modified or expanded through formal applications to OSHA, where the agency evaluates evidence of the NRTL's testing capacity, personnel qualifications, and quality systems before approval.[4] For example, in September 2025, OSHA proposed expansions incorporating UL 121201 (Nonincendive Electrical Equipment for Use in Class I and II, Division 2 and Zone 2 and 22 Hazardous Locations) into the scopes of additional NRTLs such as QPS Evaluation Services Inc., while it is already recognized for UL LLC and CSA Group.[26][22]
Testing and Certification
Applicable Standards
Nationally Recognized Testing Laboratories (NRTLs) evaluate products against a comprehensive set of safety standards approved by the Occupational Safety and Health Administration (OSHA) to ensure compliance with workplace safety requirements under 29 CFR 1910.7. These standards are drawn from various standards developing organizations (SDOs), including the American National Standards Institute/Underwriters Laboratories (ANSI/UL), Institute of Electrical and Electronics Engineers (IEEE), CSA Group (CSA), FM Global (FM), National Fire Protection Association (NFPA), International Society of Automation (ISA), National Electrical Manufacturers Association (NEMA), Telecommunications Industry Association (TIA), American Society of Mechanical Engineers (ASME), Builders Hardware Manufacturers Association (BHMA), Compressed Gas Association (CGA), Canadian Portable Lighting Systems Organization (CPLSO), and UL.[25]OSHA maintains an official "List of Appropriate Test Standards" for the NRTL Program, which currently includes over 600 standards spanning electrical, mechanical, and other safety-related categories relevant to workplace equipment.[25] Representative examples include UL 508A for industrial control panels, ANSI/AAMI ES60601-1 for medical electrical equipment, and FM 3265 for the installation of exhaust systems for air conveying of dusts, materials, and vapors.[25] Additional key standards encompass IEEE C37.13 for low-voltage AC power circuit breakers used in industrial and commercial applications, and UL 489 for molded-case circuit breakers.[25] These standards establish performance-based criteria, such as dielectric withstand tests to verify insulation integrity under high voltage, ensuring products can operate safely without posing hazards like electrical shock or fire.[25]The list is periodically updated through notices in the Federal Register to incorporate new or revised standards while removing obsolete ones, reflecting advancements in safety technology and consensus from SDOs.[26] For instance, in September 2025, OSHA proposed adding UL 121201 as a replacement for withdrawn standards like ISA 12.12.01, which covers nonincendive equipment for use in Class I and II, Division 2, and Class III, Division 1 and 2 hazardous (classified) locations, while deleting 16 outdated standards to streamline the list.[26]In the certification process, NRTLs conduct rigorous testing of products against the applicable standards from OSHA's list, verifying conformance through methods like electrical safety evaluations and environmental simulations.[9] Upon successful testing, NRTLs affix their unique certification mark to indicate compliance, allowing manufacturers to label and distribute products for use in U.S. workplaces without further OSHA intervention on the certification aspect.[1] This process ensures that only standards deemed appropriate by OSHA—those developed by accredited SDOs and aligned with NRTL capabilities—are used, promoting uniformity and reliability in safety certifications.[9]
Product Categories
The Nationally Recognized Testing Laboratory (NRTL) program encompasses 39 distinct product categories that require certification to ensure safe workplace use under OSHA regulations. These categories are specified across various standards in 29 CFR 1910 and focus on equipment and systems posing risks such as electrical shock, fire ignition, explosion, or mechanical failure in occupational environments.[8]The categories primarily address electrical conductors and equipment, which form a core group and include items like wiring devices, motors, switchgear, and transformers used in industrial settings. For instance, arc welders and x-ray equipment fall under this umbrella, requiring testing to verify insulation integrity and fault protection. Fire detection and suppression systems represent another major category, covering automatic sprinkler systems, portable fire extinguishers, fixed extinguishing systems (such as those using dry chemical, foam, or gaseous agents), and automatic fire detection devices. These ensure reliable operation in emergencies, preventing uncontrolled fire spread in workplaces.[8]Hazardous location and material handling products constitute additional key areas, targeting environments with flammable, combustible, or explosive risks. Examples include powered industrial trucks (governed by 29 CFR 1910.178), which must be certified for use in areas with ignitable concentrations of flammable gases or vapors, as well as flame arresters, check valves, and flexible connectors for handling flammable liquids. Equipment for special locations, such as Class I, II, or III hazardous areas, also requires NRTL approval to mitigate ignition sources from electrical or mechanical components. Scaffolding, hoisting machines, and related suspension scaffold units are included to address fall and structural hazards in construction and maintenance activities.[8]NRTL certification applies exclusively to products intended for workplace deployment and excludes consumer goods unless they are repurposed for occupational use, emphasizing design, construction, and performance standards that align with OSHA's safety objectives. Testing against applicable standards verifies compliance for these categories, focusing on hazard prevention without extending to non-workplace applications. The full spectrum of categories, derived from OSHA's referenced standards, includes:
Category Group
Representative Examples
Electrical Equipment
Electrical conductors or equipment; fixed electrostatic apparatus and devices; electrostatic hand spray apparatus.[8]
Fire Protection Systems
Automatic sprinkler systems; fixed extinguishing systems; portable fire extinguishers; automatic fire detection devices; employee alarm systems.[8]
Fire Doors and Closures
Self-closing fire doors; fire doors (1.5-hour B-rated); heat-actuated closing devices for dip tanks.[8]
Flammable/Combustible Liquid Handling
Flame arresters, check valves, and safety cans; pumps and self-closing faucets; flexible connectors; service station dispensing units.[8]
LPG and Gas Systems
New commercial/industrial LPG appliances; powered industrial truck LPG conversion equipment; LPG storage systems; automatic shut-off devices for portable LPG heaters.[8]
Welding and Cutting Equipment
Acetylene apparatus (torches, regulators, generators); acetylene generator compressors; acetylene piping protective devices; manifolds for fuel gas or oxygen.[8]
Industrial Trucks and Hazardous Atmosphere Equipment
Scaffolding and single-point adjustable suspension scaffolds; hoisting machines for multiple-point suspension scaffolds.[8]
Other Specialized Systems
Metal frames for windows in acetylene rooms; mechanical ventilation for automotive service stations; electrostatic fluidized beds.[8]
This categorization ensures that NRTL-approved products demonstrate resistance to workplace hazards through rigorous evaluation of their safe design and operational integrity.[8]
Importance and Impact
Benefits to Safety
The NRTL program enhances worker protection by requiring that certain workplace equipment, such as electrical devices and fire safety systems, undergo independent testing and certification to meet established safety standards, thereby reducing the risks of hazards like electrical shocks, fires, and explosions from uncertified products.[1] For instance, certification ensures compliance with standards that mitigate electrical faults, which OSHA identifies as a leading cause of workplace injuries in industries like construction and manufacturing.[4] This third-party validation provides workers with reliable assurance that approved products are safe for use, minimizing exposure to potentially defective equipment that could lead to severe incidents.[27]Employers benefit from the program's streamlined compliance framework, as they may accept certification from any OSHA-recognized NRTL without the need for additional re-testing or verification, simplifying adherence to federal safety regulations.[4] This flexibility extends to international trade, where OSHA's recognition of foreign-based NRTLs—such as those in Canada and Japan—allows employers to incorporate globally sourced certified products, facilitating efficient supply chains while maintaining safety standards.[5]On a broader scale, the NRTL program fosters innovation in safety technologies by empowering private-sector laboratories to evaluate and certify emerging products across categories like electrical systems and protective gear, encouraging manufacturers to develop advanced, compliant solutions.[1] Since its first recognitions in 1989, NRTLs have collectively certified millions of products for workplace use. Meanwhile, U.S. workplace fatality rates have sustained a decline from over 6,000 in 1990 to 5,283 in 2023.[28][29]
Relation to OSHA Enforcement
The Occupational Safety and Health Administration (OSHA) integrates Nationally Recognized Testing Laboratory (NRTL) certifications into its enforcement activities by accepting them as evidence of compliance with applicable safety standards during workplace inspections. When OSHA compliance officers conduct inspections, they verify that electrical and other specified equipment bears the appropriate NRTL certification mark, which indicates that the product has been tested and certified to meet the requirements of standards such as 29 CFR 1910.303 (Electrical) or 1910.307 (Hazardous Locations).[11][4] If equipment lacks a valid NRTL mark or uses an inappropriate NRTL for the product and site, OSHA may issue citations for violations, potentially classifying them as serious if they expose workers to substantial probability of death or serious harm.[4][11]OSHA maintains oversight of NRTLs through regular audits to ensure ongoing compliance with recognition criteria under 29 CFR 1910.7. These on-site assessments occur at least once every two years, evaluating the NRTL's testing, certification processes, and quality control systems to confirm they continue to protect workplace safety.[9] If deficiencies are identified, OSHA notifies the NRTL and requires corrective action; failure to address issues can lead to suspension or revocation of recognition after a 60-day period, during which the NRTL may rebut or appeal.[9] This oversight ties into broader protections, as OSHA's whistleblower program safeguards individuals reporting unsafe or non-compliant products certified by NRTLs, allowing anonymous complaints via dedicated forms to prompt investigations without retaliation.[30]NRTLs themselves do not perform enforcement actions or issue penalties; their role is limited to testing and certification, while OSHA retains authority over compliance violations in workplaces. OSHA handles all enforcement, including assessing civil penalties for serious violations up to $16,550 per instance as of January 15, 2025, adjusted annually for inflation.[31][32] This separation ensures that NRTL certifications serve as a preventive measure, but ultimate accountability for safe equipment use falls under OSHA's regulatory framework.[4]