Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

July 7, 2003

Mr. Joseph C. Caldwell
Government Liaison
Pipeline Safety Regulations
2111 Wilson Boulevard
Suite 700
Arlington, Virginia 22201

Re: What constitutes an acceptable means of locating underground utilities under 29 CFR 1926.651(b)(2) and (b)(3).

Dear Mr. Caldwell:

This is in response to your letter dated September 18, 2002, to the Occupational Safety and Health Administration (OSHA). You ask about the meaning of certain terminology in 29 CFR 1926.651(b)(2) and (b)(3) regarding methods that may be used to locate underground utilities, and whether hydro-vacuum excavation complies with that standard.
1 We apologize for the long delay in responding.

We have paraphrased your questions as follows:

Question: Section 1926.651 contains several requirements that relate to the safety of employees engaged in excavation work. Specifically, paragraphs (b)(2) and (b)(3) relate in part to the safety of the means used to locate underground utility installations that, if damaged during an uncovering operation, could pose serious hazards to employees.

Under these provisions, what constitutes an acceptable method of uncovering underground utility lines, and further, would the use of hydro-vacuum excavation be acceptable under the standard?



Two provisions in 29 CFR 1926 Subpart P (Excavations), §1926.651(Specific excavation requirements), govern methods for uncovering underground utility installations. Specifically, paragraph (b)(2) states:

When utility companies or owners cannot respond to a request to locate underground utility installations within 24 hours * * * or cannot establish the exact location of these installations, the employer may proceed, provided the employerdoes so with caution, and provided detection equipment or other acceptable means to locate utility installations are used. (Emphasis added.)

Paragraph (b)(3) provides:

When excavation operations approach the estimated location of underground installations, the exact location of the installations shall be determined by safe and acceptable means. (Emphasis added.)

Subpart P does not contain a definition of either "other acceptable means" or "safe and acceptable means."

The preambles to both the proposed rule and the final rule discussed the rationale behind the wording at issue. For example, the preamble to the proposed rule, 52 FR 12301 (April 15, 1987), noted that a 1972 version of this standard contained language that specified "careful probing or hand digging" as the means to uncover utilities. The preamble then noted that an amendment to the 1972 standard later deleted that language "to allow other, equally effective means of locating such installations." The preamble continued that in the 1987 proposed rule, OSHA again proposed using language in Section (b)(3) that would provide another example of an acceptable method of uncovering utilities - "probing with hand-held tools." This method was rejected in the final version of 29 CFR Part 1926. As OSHA explained in the preamble to the final rule, 54 FR 45916 (October 31, 1989):

OSHA received two comments * * * and input from ACCSH [OSHA's Advisory Committee on Construction Safety and Health] * * * on this provision. All commenters recommended dropping 'such as probing with hand-held tools' from the proposed provision, because this could create a hazard to employees by damaging the installation or its insulation.

OSHA then concluded its discussion relative to this provision by agreeing with the commentators and ultimately not including any examples of "safe and acceptable means" in the final provision.

Thus, the regulatory history behind these provisions indicates that the means used must be both effective - that is, accurate - and safe. Digging with traditional hand-held tools, such as a shovel, can damage some underground utilities (such as electrical lines) and therefore is not acceptable.

Hydro-vacuum excavation
It is our understanding that some hydro-vacuum excavation equipment, especially the smaller machines, can be adjusted to use a minimum amount of water and suction pressure. When appropriately adjusted so that the equipment will not damage underground utilities (especially utilities that are particularly vulnerable to damage, such as electrical lines), use of such equipment would be considered an acceptable means of locating underground utilities. However, if the equipment cannot be adjusted (which, we understand, is typical for large machines), or cannot be sufficiently adjusted, then this method would not be acceptable under the standard.

If you need any 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





1We understand that although you are based in Virginia, which has an approved state OSHA program, you have asked us this question with respect to the Federal OSHA requirements. [ back to text ]