OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.gov.

January 22, 2004

Mr. James R. Rhudy
(by fax)

Re: Whether, in construction work, portable ladders may be used on tank builders' scaffolds during the scaffold dismantling process; §1926.451.

Dear Mr. Rhudy:

This is in response to your telephone inquiry on July 14th, 2003 and related subsequent e-mail on July 15th, 2003, to the Occupational Safety and Health Administration (OSHA). You ask about the requirements in the construction scaffolds standard, 29 CFR Part 1926 Subpart L, regarding the use of a portable ladder on tank builders' scaffolds during the dismantling process. We received a response from you on August 27, 2003, to our follow-up e-mail dated July 17, 2003, that requested more information. We apologize for the delay in issuing this letter.

We have paraphrased your question as follows:

Question: The construction scaffolds standard (Subpart L) contains various provisions that address safe work practices relative to the use of scaffolds, including tank builders' scaffolds.

In the process of dismantling these scaffolds, we use portable ladders on the scaffold so that the worker can reach and remove welded brackets. The nonskid base of the ladder rests on the scaffold board while its top rests against the tank structure. Our practice is to have the worker who climbs the ladder wear a body harness that is hooked to either an independent vertical lifeline or to a retractable device that is tied off independent of the ladder. The ladder is also held during the dismantler's climb. Also, the portion of the scaffold below the section that is being removed is attached (restrained) to the tank.

Is this use of portable ladders during the dismantling process permissible?



Subpart L requires the employer to assess the feasibility of safe access for employees dismantling supported scaffolds. This determination must be based upon a site specific evaluation by a competent person. Specifically, in §1926.450, the scope and pertinent definitions are set forth as follows:

(a) Scope and application.
This subpart applies to all scaffolds used in workplaces covered by this part.
* * *
(b) Definitions.
* * *
Competent person means one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.
* * *
Tank builders' scaffold means a support scaffold consisting of a platform resting on brackets that are either directly attached to a cylindrical tank or attached to devices that are attached to such a tank.

Section 1926.451 addresses safe access in general, including the use of ladders, and, significantly, access for employees engaged in dismantling supported scaffolding:

* * *
(e) Access. This paragraph applies to scaffold access for all employees. Access requirements for employees erecting or dismantling supported scaffolds are specifically addressed paragraph (e)(9) of this section. [Emphasis added.]
* * *
(2) Portable, hook-on, and attachable ladders (Additional requirements for the proper construction and use of portable ladders are contained in subpart X of this part
* * *
(9)* * *access for employees erecting or dismantling supported scaffolds shall be in accordance with the following:
(i) The employer shall provide safe means of access for each employee erecting or dismantling a scaffold where the provision of safe access is feasible and does not create a greater hazard. The employer shall have a competent person determine whether it is feasible or would pose a greater hazard to provide, and have employees use a safe means of access. This determination shall be based on site conditions and the type of scaffold being erected or dismantled. [Emphasis added.]
(ii) Hook-on or attachable ladders shall be installed as soon as scaffold erection has progressed to a point that permits safe installation and use.

As noted in the Preamble at 61 FR 46025 (August 30, 1996):

The Agency agrees that there are some situations where an exemption from final rule paragraph (e) would be appropriate. * * * OSHA finds that it is appropriate for employers to be able to obtain relief from the access requirements when such relief has been determined, on a case by case basis, to be necessary. Accordingly, the Agency has added final rule paragraph (e)(9) * * *.

Section 1926.451(g) (Fall protection) contains, among others, fall protection requirements that specifically relate to the dismantling and erection of supported scaffolds. As with the applicability of the access provisions, the feasibility of fall protection for dismantlers is determined by a competent person.

Section 1926.451(g)(2) provides:

* * * the employer shall have a competent person determine the feasibility and safety of providing fall protection for employees erecting or dismantling supported scaffolds. Employers are required to provide fall protection for employees erecting or dismantling supported scaffolds where the installation and use of such protection is feasible and does not create a greater hazard.

Finally, §1926.451(f) contains various provisions that govern the "use" of scaffolds. Significantly, §1926.451(f)(15) addresses the use of ladders on scaffolds:

Ladders shall not be used on scaffolds to increase the working level height of employees, except on large area scaffolds [a defined term in this Subpart]1 where employers have satisfied the following criteria:
(i) When the ladder is placed against a structure which is not part of the scaffold, the scaffold shall be secured against the sideways thrust exerted by the ladder;
(ii) The platform units shall be secured to the scaffold to prevent their movement;
(iii) The ladder legs shall be on the same platform or other means shall be provided to stabilize the ladder against unequal platform deflections, and
(iv) The ladder legs shall be secured to prevent them from slipping or being pushed off the platform.

In sum, §1926.451(e) and (g) contain access and fall protection requirements that, depending upon a feasibility determination by a competent person, may apply to employers and employees engaged in dismantling scaffolding. Thus, the potential application of any fall protection requirements, and other access provisions and/or other relevant provisions in Subpart X governing the use of portable ladders, would be subject to an initial feasibility evaluation by a competent person.

On the other hand, §1926.451(f)(15) contains mandatory limitations and requirements relative to the use of ladders on scaffolds. Use of a portable ladder contrary to that provision, such as on a type of scaffold not specified and/or on a smaller surface area, would violate the standard. The preamble at 61 FR 46062 indicates the purpose of that provision:

This provision was intended to ensure that workers were provided with a secure work platform, and to eliminate the hazard of tipping caused by portable ladders exerting a sideways thrust on scaffold systems.

OSHA has previously indicated the types of items that might be considered in an access feasibility analysis by a competent person. In a January 2, 2002, interpretation letter to Ms. Carmen Shafer, the Agency noted that a "safe means of access" is not defined in the standard, but stressed that the goal of §1926.451(e)(9) is to eliminate the exposure of employees erecting or dismantling supported scaffolds to access hazards. The letter then indicated that the general access requirements in §1926.451(e) and the provisions in Part 1926 Subpart X reflect "principles of safe access."

Among the general principles mentioned were:

hand-holds, and stepping surfaces that are: (1) level or will allow workers to maintain their balance; (2) sufficiently close to one another so that workers can move from one to the next without falling; (3) spaced evenly enough so that workers can find the next stepping surface without seeing it while ascending and descending; and (4) sufficiently strong and stable. [Emphasis added.]


In your scenario, the employer, in consultation with a competent person, must determine the feasibility of using a portable ladder as a means of safe access on a tank builders' scaffold. Pertinent general access provisions (and Subpart X as incorporated) in light of site conditions need to be evaluated. The feasibility of such access might be affected by the stability of the ladder on the planking, the stability of the scaffolding and the capacity of the scaffolding. Also, the feasibility of fall protection must be considered.

The materials that you provided as well as other research suggest that your use of a portable ladder, in essence, constitutes safe access. However, the described use of a portable ladder on a tank builders' scaffold does violate §1926.451(f)(15).

As previously noted, §1926.451(f)(15) addresses the hazard of "tipping caused by portable ladders exerting a sideways thrust. . . ." Your e-mail dated July 14, 2003, indicated that your described use of a portable ladder minimizes the risk of this hazard. You stated:

The ladder base would be on the scaffold board and the top of the ladder would rest against the structure. The scaffold will not move because the scaffold bracket is attached to the structure. The scaffold boards will not move because the outer most board is against the post and the other board is against the outer most board.

Additionally, Section 2.3 of your company's "safety standards on scaffold erection procedures" that were forwarded to this office includes the following:

19. Secure all scaffold planks with chain load binders, or key channels, j-hooks, and bullpins if required.

Finally, you stated that the employee on the ladder wears a body harness that is tied off independent of the ladder.

OSHA considers a violation to be de minimis when an employer complies with the clear intent of the standard but deviates from its particular requirements in a manner that has no direct or immediate impact on the safety and health of workers. In such instances, no citation is issued.

In your scenario, the procedures as we understand them, for your use of the portable ladder on a tank builders' scaffolds would be sufficient to prevent the hazard addressed by §1926.451(f)(15). Those procedures include the following:

  • The portions of the scaffold below the section being removed are attached (restrained) to the tank to the extent necessary to meet the requirements of §1926.451 (which includes resisting the lateral loads imposed by the use of the ladder);
  • Welded brackets, bracket arms and handrail posts are used to secure the scaffold planks; in addition, binders; hooks and bullpins are used when the competent person determines that they are needed;3
  • A worker holds the ladder while the other worker is on it;
  • The ladder has a nonskid base; and
  • The dismantler uses personal fall protection while on the ladder.



Subject to your compliance with §1926.451(f)(15)(iii), which requires that ladder legs be on the same platform or other means be taken to similarly stabilize the ladder, you have provided a working environment that is as safe for workers engaged in the dismantling activity as that provided for in §1926.451(f)(15).

Thus, the above-described use of a portable ladder in your dismantling process (including compliance with §1926.451(f)(15)(iii)) would only constitute a de minimis violation of §1926.451(f)(15).

Finally, it should be noted that although §1926.451(e)(9)(ii) requires the use of a hook-on or attachable ladder "as soon as scaffold erection has progressed to a point that permits safe installation and use," it does not rule out the use of other types of ladders during dismantling.

If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Russell B. Swanson, Director
Directorate of Construction



1 Section 1926.450 defines "Large area scaffold" as:

a pole scaffold, tube and coupler scaffold, systems scaffold, or fabricated frame scaffold erected over substantially the entire work area. For example: a scaffold erected over the entire floor area of a room. [back to text]



2 However, in your email, you have already stipulated that you require the dismantler on the portable ladder to wear a body harness that is hooked to either an independent vertical lifeline or to a retractable device that is tied off independent of the ladder. [back to text]



3 Under §1926.451(f), the dismantling must be subject to the supervisory control of a competent person qualified in scaffold dismantling. [back to text]