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Standard Interpretations - Table of Contents
• Standard Number: 1910.178(m)(5); 1910.178(m)(5)(ii); 1910.178(m)(5)(iii); 1926.302; 1926.302(e); 1926.302(e)(6); 1926.600; 1926.600(a)(3); 1926.600(a)(3)(i); 1926.600(a)(3)(ii); 1926.701(b); 1926.702(a); 1926.702(b)

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

May 11, 2005

Mr. Peter Kuchinsky, II
Safety Trainer/Consultant
Construction Building Analysts
1770 Wolverine Way
Vista, CA 92084

Re: Requirements for leaving construction equipment and powder-actuated tools unattended on a construction building site; impalement protection from reinforcing steel for masonry workers on a scaffold; §1926.701(b). §§1926.302(e)(6), 1926.600(a)(3)

Dear Mr. Kuchinsky:

This is in response to your April 27, 2004, letter to the Occupational Safety and Health Administration (OSHA) asking for clarification of the requirements under 29 CFR 1926.600. Your questions regard unattended construction equipment and the requirements under §1926.302 for unattended powder-actuated tools. We apologize for the delay in responding.

We have paraphrased your questions below:

Question 1a: What OSHA requirements apply to an employer leaving construction equipment such as bobcats, backhoes, and trenchers unattended and running on a construction building site?

Answer: Title 29 CFR 1926.600(a)(3) states:
(i) Heavy machinery, equipment, or parts thereof, which are suspended or held aloft by use of slings, hoists, or jacks shall be substantially blocked or cribbed to prevent falling or shifting before employees are permitted to work under or between them. Bulldozer and scraper blades, end-loader buckets, dump bodies, and similar equipment, shall be either fully lowered or blocked when being repaired or when not in use. All controls shall be in a neutral position, with the motors stopped and brakes set, unless work being performed requires otherwise. [Emphasis added.]
(ii) Whenever the equipment is parked, the parking brake shall be set. Equipment parked on inclines shall have the wheels chocked and the parking brake set.
The underlined portion of §1926.600(a)(3)(i) above requires that construction equipment such as bulldozers and scraper blades, end-loader buckets, and dump bodies be either fully lowered or blocked when not in use, with all controls in a neutral position, the motor stopped, and the brakes set. This section of the standard explicitly provides that the equipment list in the provision is not exclusive and that construction equipment similar to that listed also must meet these requirements.

Bobcats, backhoes, and trenchers share similar characteristics with bulldozers, scraper blades, end-loader buckets, and dump bodies. Each of these has an attachment or feature (such as a bucket or platform) that raises and lowers horizontally and/or vertically by hydraulic actuation. Furthermore, in each type of machine there is the hazard that the attachment/feature may unexpectedly drop when left in the raised position and unattended. Therefore, bobcats, backhoes, and trenchers fall within the provision's scope as similar equipment, and the employer is required to fully lower or block the equipment's attachment/feature when the equipment is not in use, placing all controls in neutral, the motor off, and brakes set.

In addition, under §1926.600(a)(3)(ii), when equipment such as a bobcat, backhoe, or trencher is "parked," the parking brake must be set. If the bobcat, backhoe, or trencher is on an incline when parked, in addition to setting the brake, the wheels must also be chocked. (We discuss what "parked" means in Question 1b below.)

Question 1b: Under §1926.600(a)(3), when is the equipment considered to be "not in use" or "parked"?

Answer: Not in use
The standard does not define the terms "not in use" or "parked." In light of the purpose of the standard and the context of this provision, "not in use," normally means when the equipment operator is not at the equipment's controls.

However, we are mindful of a General Industry provision for industrial trucks, 29 CFR 1910.178(m)(5). It sets forth both a definition and requirements for industrial trucks used in general industry (not construction):
(ii) A powered industrial truck is unattended when the operator is 25 ft. or more away from the vehicle which remains in his view, or whenever the operator leaves the vehicle and it is not in his view.

(iii) When the operator of an industrial truck is dismounted and within 25 ft. of the truck still in his view, the load engaging means shall be fully lowered, controls neutralized, and the brakes set to prevent movement.
Although these provisions do not apply to construction or earth-moving equipment, they address some of the same type of hazards. After considering the approach that was taken in §1910.178(m)(5) and the hazards associated with construction equipment, we have determined that, for construction equipment such as bobcats, backhoes, and trenchers, leaving the motor running with the operator away from the controls will be considered a de minimis violation
2 of §1926.600(a)(3) where all of the following are met: the attachment is lowered, the controls are in the neutral position, the brakes are set, all manufacturer provided and recommended safety measures are utilized, and the operator is within 25 feet (and still in view) of the equipment.

In the context of this provision, this type of equipment is "parked" when the equipment is not going to be in use for a substantial period of time. An example would be where the equipment is used at the start of the work day and will not be used again that day.

Question 2: Section 1926.302(e)(6) states, with regards to powder-actuated tools, that "loaded tools shall not be left unattended." What is OSHA's definition of "unattended" under 29 CFR 1926.302? Would the definition of unattended in §1910.178(m)(5)(ii) for Powered Industrial Trucks be applicable?

Answer: Section 1926.302(e)(6) states:
(e) Powder-actuated tools.
* * *
Loaded tools shall not be left unattended.
There is no definition for "unattended." provided in 29 CFR Part 1926 Subpart I (Tools — Hand and Power). Although the definition of unattended in 29 CFR 1910.178(m)(5)(ii) for Powered Industrial Trucks is not applicable,
3 the underlying principle is relevant, since the term "unattended" is used in a similar context.

Both standards address the concept of how close an operator needs to be to be considered to be attending equipment. In the case of §1926.302(e)(6), the hazard is that, if the tool is unattended, a worker who is not knowledgeable and not authorized to use a powder actuated tool may pick it up and use it improperly. For example, the authorized worker may have loaded the tool with a cartridge designed to shoot a nail into concrete. An unauthorized worker may not know that different cartridges are used for different materials. If the unauthorized worker used the tool to nail into a 2x4 in a framed wall, it could penetrate all the way through and exit the 2x4 and strike a worker standing on the other side of the wall.

As long as the authorized worker is less than 25 feet away and in view of the tool, he/she would be able to intercede if another worker picked up the tool. Therefore, the tool is considered to be attended when the authorized worker, while in view of the tool, is less than 25 feet away.

Question 3: Scenario: masonry workers are on a scaffold. On the working (wall) side of the scaffold, rebar protrudes up from the wall that is under construction. The top of the rebar is higher than the scaffold planking that the workers are standing on, but lower than head height. Are the workers required to be protected from impalement?

Answer: OSHA's concrete and masonry standards provide specific protections against the hazards of protruding reinforcing steel in §1926.701(b), which states:
(b) Reinforcing steel. All protruding reinforcing steel, onto and into which employees could fall, shall be guarded to eliminate the hazard of impalment. [Emphasis added.]
As explained in the preamble to the final rule revising Subpart Q (June 16, 1988, 53 FR 22617 and 22618), this is a change from the previous rule, which required protection when an employee was "above" reinforcing steel. The language was changed to make it clear that the entire body of an employee does not have to be "above" protruding steel for the requirement to apply. Instead, the standard requires the guarding of protruding reinforcing steel whenever employees could fall into or onto it and thereby become impaled:
The final rule differs from the proposed provision which was located in §1926.702(a) and the existing provision which was located in §1926.702(b)(2) ... The existing rule required only that the employer guard vertically protruding reinforcing steel when employees are working above it.

... OSHA's intent is to eliminate the hazard of impalement completely. OSHA did not intend that the use of the word "above" would be construed to mean that the entire body of an employee would have to be "above" the protruding steel. OSHA realizes that employees could be, in fact, often are, in a position where only part of their body is above the protruding steel, such as walking alongside of protruding rebar where as TSA points out, the employee could trip and then fall into the steel. Likewise, there are situations where the steel is protruding from a horizontal direction and employees could fall or trip into the steel and become impaled. To properly protect employees from the hazard of impalement, OSHA has revised the provision to state clearly that all protruding reinforcing steel is to be guarded whenever employees could fall into or onto the steel and thereby become impaled .... [Emphasis added.]
In your scenario, there is rebar adjacent to the scaffold planking and the top of the rebar is below the head height of those working next to it. Whether the rebar would present an impalement hazard would depend on factors such as how close the rebar is to the scaffold platform and its height. In general, in a scenario such as the one you describe, the rebar typically would present an impalement hazard to a falling worker.

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 Neither §1926.600(a)(3)(i) nor (ii) addresses situations where the equipment is "in use" but the operator is away from the controls. One such example is when the operator of a cement mixer is setting the chutes at the back of the truck in preparation for a pour while the drum is rotating. In that instance the mixer is operating (the drum is rotating) but the operator is not at the controls. We have not addressed that type of situation in this letter.
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2 Under OSHA's de minimis policy, de minimis violations are those that have no direct or immediate relationship to safety or health. Consequently, no citation is issued.
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3 Section 1910.178(m)(5)(ii) states, "A powered industrial truck is unattended when the operator is 25 ft. or more away from the vehicle which remains in his [/her] view, or whenever the operator leaves the vehicle and it is not in his view."
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Standard Interpretations - Table of Contents

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