Nationally Recognized Testing Laboratories, OSHA and Electrical Safety Standards

OSHA Safety Standards

What do a printer, copier, desktop computer, telephone, employee alarm, water cooler, string of Christmas lights, electric heater, air conditioner, electric generator, surveillance camera, fire door, exit component, fire extinguisher, electrical conduit, conductor, electric motor, powered industrial truck, acetylene torch, and liquefied petroleum gas oven have in common?

In accordance with OSHA Safety Standards, any of these products used in a workplace must be approved (i.e., tested and certified) by a Nationally Recognized Testing Laboratory (NRTL) to help ensure that they can be used safely in the workplace. OSHA requires NRTL approval for 37 different types of products, which are described at Electric equipment is the largest of these product categories.

The requirements for NRTL approval apply where these products are used in workplaces subject to OSHA’s jurisdiction. These include the vast majority of private employers in the United States and its territories, and most Federal Government places of employment. The requirements also apply to State and local government places of employment in States that have received OSHA approval to administer their own occupational safety and health program (referred to as “State Plan States”).

Not Just Testing Labs
NRTLs are qualified private organizations that meet the requirements in OSHA regulations under 29 CFR section 1910.7 to perform independent safety testing and product certification. OSHA makes this determination under its NRTL Program, which is part of OSHA’s Directorate of Science, Technology, and Medicine.

NRTLs may be based in the United States or in other countries. Currently, 16 NRTLs are established in the United States, and 2 NRTLs are foreign-based. A listing of current NRTLs is at The recognition process (described under section 1910.7) is the same for all organizations; however, if an applicant is foreign-based, OSHA must consider the policy of the foreign government concerning its acceptance or recognition of test labs and NRTLs based in the United States. Such acceptance is not a prerequisite for OSHA to grant the applicant recognition.

The term “NRTL” may be a little misleading. It not only means that an organization must be a test lab that performs product safety testing. In addition, OSHA requires the same organization to operate a product-certification program that includes listing and labeling and follow-up inspection programs. For a particular product, safety testing activities involve the NRTL ensuring that a representative unit of that product has necessary safety features.

The related certification activities involve the NRTL ensuring, again for that particular product, that all manufactured units of the product have the necessary safety features. Proper product testing and certification require a great deal of special expertise, effort, and resources. OSHA does not perform any product approvals; OSHA relies on third parties, NRTLs, to do this work.

Product Approval Requirements Predate OSHA
Even before OSHA came into existence in 1971, national consensus organizations and other code developers recognized the need to test and certify products to meet the safety requirements of their voluntary standards. For example, the National Fire Protection Association (NFPA) has long required safety testing of electric equipment to meet various provisions of the National Electrical Code (NEC). The NEC is the dominant electrical safety code in use in the United States.

During OSHA’s first two years, the Agency adopted many established Federal standards and national consensus standards as OSHA standards under section 6(a) of the Occupational Safety and Health Act (OSH Act), 29 U.S.C. 655(a). Many of these standards contained requirements for equipment to be “approved,” “listed,” or “labeled.” In 1988, OSHA established regulations for the NRTL Program. These regulations imposed no additional regulatory burden on employers but clarified what approval meant and formally established a process by which organizations would be recognized as NRTLs. OSHA established the regulations, in part, as a result of a successful lawsuit by an organization alleging that the “approval” requirements essentially had designated only two organizations as acceptable to OSHA.

Most of OSHA’s standards that require NRTL approval are found in the Agency’s General Industry standards, in 29 CFR Part 1910. For example, 29 CFR 1910.303(a) (read together with the definitions of “approved” and “acceptable” in §1910.399) imposes a general requirement for electric equipment or products to be approved by NRTLs. The term most often used in the standards to require NRTL approval is the term approved. Terms in those standards having similar meaning include certified, listed, and listed and labeled. A comprehensive listing of NRTL approval requirements can be found on OSHA’s web site at

Similar provisions for third party approval of products exist to varying degrees in other OSHA standards. OSHA’s Construction Standards, 29 CFR Part 1926, requires that approval of electric equipment be provided by a “qualified testing laboratory” (QTL). OSHA’s definitions for NRTLs and QTLs are essentially equivalent.

The NRTL’s Mark is on the Product
NRTLs generally work with product manufacturers to test and certify (i.e. approve) products. In approving a product for the manufacturer, the NRTL issues a certification document and permits the manufacturer to apply the NRTL’s registered certification mark or symbol on all units of the product manufactured. This certification mark on a product is important in that it assures the user that a particular NRTL has tested and certified that specific product. If it is not feasible to apply the certification mark directly on an NRTL-approved product, the mark should appear on the smallest packaging of the product. OSHA’s web page shows the certification marks generally used by each NRTL. The certification mark(s) used by each NRTL is shown at

OSHA does not require the use of certification marks containing the initials “NRTL”. Also, OSHA does not own such a certification mark. However, a few NRTLs have voluntarily included these initials in their regular certification marks. With or without the use of the “NRTL” initials, the product marking of NRTLs recognized for the same product safety standard is equivalent in designating product conformance to that standard.

Each NRTL Has a Scope of Recognition
The NRTL’s scope of recognition specifies the types of products it can approve through a listing of the “appropriate test standards” the NRTL may use in approving products. To see each NRTL’s scope, go to and click the name of one of the NRTLs. As required by Section 1910.7, an appropriate test standard must be a U.S. consensus-based test standard that is developed and maintained by a U.S. standards developing organization (SDO). International test standards used in European and other countries may be applied if they have been harmonized to U.S. requirements by a U.S. SDO, thus making them “appropriate.”

NRTLs have been recognized for more than 600 individual product safety standards, which cover thousands of individual types of products and, in actual usage, cover literally billions of certified products. A list of these standards is available at OSHA’s web site, which provides an informational web page for each NRTL that details its scope of recognition. That scope also includes “sites,” the facilities where certain key activities can be performed, and “programs,” under which the NRTL can use other parties in performing activities necessary for product testing and certification. These other parties include other NRTLs, other non-NRTL independent testing labs, and product manufacturers.

Minor Exceptions
In general, under 29 CFR Part 1910, products required to be approved must be NRTL approved. However, there are a few exceptions. Most notably, for electric products, there are two exceptions. If the electric products are of a kind that no NRTL approves, then OSHA allows approval of the products by a Federal agency or by a State or local code authority that enforces NEC workplace safety provisions. The other exception concerns “custom-made equipment,” which designates equipment designed, made for, and used by a particular customer (i.e., unique or one-of-a-kind items). In this case, the employer must demonstrate safety based on test data provided by the manufacturer. As can be seen, these exceptions are very narrow.

As indicated earlier, NRTLs can use testing done by other parties under certain programs allowed by OSHA. These other parties include product manufacturers and can be located anywhere in the world. While using these programs can minimize the work that the NRTL must accomplish itself, the NRTL must exercise adequate control to ensure that other parties are doing the activities appropriately. Nonetheless, these programs can reduce the time and cost necessary for product certification.

“CE” Mark and Foreign Testing Organizations
The CE mark is a generic marking allowed by the European Union (EU) to indicate that a product meets requirements in the EU for product safety and is unrelated to the requirements for product safety in the United States. In the United States, a product used in the workplace that is required to be NRTL approved must have the specific mark of one of the NRTLs that is recognized to test and certify this type of product. For this reason, OSHA must recognize a foreign testing and certification organization as an NRTL before its product certifications will be considered acceptable to OSHA.

More information Is Available

The OSHA website at provides more information on the various aspects of OSHA’s requirements for approval of products by NRTLs. Once on the OSHA home page, choose “N” from the site index at the top and select “Nationally Recognized Testing Labs (NRTL)” from the subject listing or go to If clarification or further information is needed, call (202) 693-2110 and request to speak with a member of the NRTL Program staff.

Organizations Recognized by OSHA

The following organizations have been recognized by OSHA in accordance with 29 CFR 1910.7 to test and certify equipment or materials (products) requiring approval by certain OSHA safety standards:

Canadian Standards Association (CSA)
(also known as CSA International)
178 Rexdale Boulevard
Etobicoke (Toronto), Ontario M9W 1R3

Communication Certification Laboratory, Inc. (CCL)
1940 West Alexander Street
Salt Lake City, Utah 84119

Curtis-Straus LLC (CSL)
Littleton Distribution Center
One Distribution Center Circle, Suite #1
Littleton, MA 01460

FM Approvals LLC (FM)
(formerly Factory Mutual Research Corporation)
1151 Boston-Providence Turnpike
P.O. Box 9102
Norwood, Massachusetts 02062

Intertek Testing Services NA, Inc. (ITSNA)
(formerly ETL, Inchcape)
3933 U.S. Route 11
Cortland, New York 13045

MET Laboratories, Inc. (MET)
914 West Patapsco Avenue
Baltimore, Maryland 21230

National Technical Systems, Inc. (NTS)
1146 Massachusetts Avenue
Boxborough, Massachusetts 01719

NSF International (NSF)
789 Dixboro Road
Ann Arbor, Michigan 48105

QPS Evaluation Services Inc. (QPS)
81 Kelfield Street, Unit 8
Toronto, Ontario, M9W 5A3

SGS U. S. Testing Company, Inc. (SGSUS)
(formerly U.S. Testing/California Division)
291 Fairfield Avenue
Fairfield, New Jersey 07004

Southwest Research Institute (SWRI)
6220 Culebra Road
Post Office Drawer 28510
San Antonio, Texas 78228

TÜV SÜD America, Inc. (TUVAM)
5 Cherry Hill Drive
Danvers, Massachusetts 01923

TÜV SÜD Product Services GmbH (TUVPSG)
Ridlerstrasse 65, D-80339
Munich, Germany

TUV Rheinland of North America, Inc. (TUV)
12 Commerce Road
Newtown, Connecticut 06470

Underwriters Laboratories Inc. (UL)
333 Pfingsten Road
Northbrook, Illinois 60062

Wyle Laboratories, Inc. (WL)
7800 Highway 20 West
P.O. Box 077777
Huntsville, Alabama 35807

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Mike is a finance industry executive with expertise in test, IT and avionics equipment acquisition, resale, residual valuation, leasing, renting and consignment.
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