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 https://www.osha.gov.

February 11, 1993

Mr. Kerry E. Saltzman
Fox and Grove
311 South Wacker Drive
Suite 6200
Chicago, Illinois 60606-6622

Dear Mr. Saltzman:

This is in response to your November 17, letter requesting an interpretation of the Occupational Safety and Health Administration (OSHA) standards addressing the use of explosives (29 CFR 1926.900(j)). I apologize for the delay of this response.

With regard to whether the requirement to conduct blasting operations, insofar as possible, between sunup and sundown applies to blasting which is completely contained within a vessel, the answer is no. This requirement only addresses outdoor applications where daylight can help visually ensure that all personnel are removed or kept out of the blast hazard area.

Based on the information you provided concerning your process of removing refractory lining and iron residue, it appears that conducting blasting operations between 4:00 a.m. and 7:00 a.m. when employee exposure is at a minimum meets the intent of 1926.900(j).

Again, we apologize for the delay in our response and if we can be of any further assistance, please contact me or Mr. Dale R. Cavanaugh of my staff at (202) 219-8136.


Roy F. Gurnham, Esq., P.E.
Office of Construction and Maritime
Compliance Assistance

November 17, 1992

Roy Gurnham
Office of Construction Maritime
Compliance Assistance
200 Constitution Ave N.W.
Room N-3610
Washington, D.C. 20210

Re: Request for clarification and/or interpretation of blasting and explosives standard contained in 29 CFR 1926.900(j)

Dear Mr. Gurnham:

Davy-Songer, Inc. (hereafter referred to as either "Davy-Songer" or the "Company") submits this request for a clarification and/or interpretation of the standard promulgated in 29 CFR 1926.900(j) concerning blasting and the use of explosives as that standard applies to Davy-Songer's construction work in the renovation and repair of blast furnaces at steel producing facilities. That standard reads in pertinent part:

(j) Insofar as possible, blasting operations above ground shall be conducted between sunup and sundown.

As is explained below, the standard is ambiguous when applied to Davy-Songer's blasting operations because it usually conducts its blasting in either the early morning hours between work shifts or during the evening work shift when there are reduced numbers of employees at the job site. Davy-Songer's preferred method of blasting is substantially safer than if it were to blast only "between sunup and sundown" because there are substantially fewer employees on the job site when blasting is done in non-daylight hours. Therefore, while it is "possible" for the Company to conduct all of its blasting "between sunup and sundown", to do so would substantially increase, rather than decrease, employee exposure to hazards.

Davy-Songer, accordingly, requests the Department to clarify that the Company's method of conducting blasting in the early morning hours is not contrary to the standard articulated in 29 CFR 1926.900(j).


Davy-Songer is a company engaged in the business of construction, renovation and repair of blast furnaces, coke ovens, and other structures utilized in the process of making steel. The Company primarily contracts with the owners of steel producing facilities to perform its construction services at the owners' premises. Davy-Songer is based in Washington, Pennsylvania and is currently performing and plans to perform construction at steel plants located throughout the country, including in Pennsylvania, Indiana, Michigan, Alabama, Maryland, Ohio and West Virginia.

A blast furnace is a structure used to produce iron. The iron, in turn, is converted to steel. Approximately every five years, the refractory lining (a specialized fire brick) of the blast furnace must be completely torn down and rebuilt due to deterioration caused by extreme heat and residue. The tearing down process usually requires dynamiting in two areas of the blast furnace, the "dustcatcher" and the "salamander." The dustcatcher is a pollution control device that is attached to the blast furnace. The dustcatcher is designed to capture and store dust residue that is created in the manufacturing process. The dust solidifies and hardens and the only effective method of removing the hardened dust is by blasting.

The "salamander" is the iron residue that has been processed through the furnace and accumulated at the furnace's base. When the furnace is quenched ("cooled") for the repair work, the iron cools and hardens and, like the residue contained in the dustcatcher, must be broken up through dynamiting before it can be removed. The blasting on both the dustcatcher and the salamander is completely contained within the vessels. There is, therefore, no danger of flying debris created by the blasting.

Typically, Davy-Songer conducts its rebuilding work on blast furnaces in two shifts. The first shift usually begins at around 7:00 a.m. and ends at 5:00 p.m. The second shift usually runs from 6:00 p.m. until 4:00 a.m. On average, there are approximately 300 construction workers on each shift. Optimally, Davy-Songer conducts its blasting operations between shifts in the hours from 4:00 a.m. to 7:00 a.m. Occasionally, Davy-Songer conducts blasting during the evening shifts after completely clearing the job site of all employees who are not engaged in the actual blasting operations.


By conducting its blasting operations in the early morning hours between work shifts and at slack periods during the evening shift, Davy-Songer is promoting employee safety for several critical reasons.

First, by conducting blasting between shifts, the only employees who are on the job site are Davy-Songer employees who are actually involved in the blasting operations. There are no steel mill employees on the site at that time. Total employee exposure to the hazards is, thus, reduced by over 95%. Moreover, the relatively few Davy-Songer employees who remain on the job site are actively involved in the blasting operations and are aware of both the location of the blasting and the time when the charges are scheduled to go off. When Davy-Songer conducts its blasting operations during the evening shifts, employee exposure is also limited because the number of steel mill employees on the mill premises is greatly reduced. Davy-Songer also takes great efforts to ensure that all of its employees, as well as all steel mill employees, are cleared from the job site during the blasting operations.

Second, because there are substantially fewer radio transmissions during the evening shift and in the hours between 4:00 a.m. and 7:00 a.m., the likelihood of accidental discharge of blasting caps by an errant radio transmission is reduced enormously. See 29 CFR 1926.900(k). The steel mill owners utilize radios for cranes, railroads and other production equipment. The radio transmissions increase during production hours but substantially decrease during the late evening shift hours and between shifts.

Third, visibility is not a problem. As part of its regular construction work, Davy-Songer provides substantial artificial lighting around its projects so that work can continue during the evening shift. Consequently, the area around the work site is always extremely well-lit in the night and in the early morning hours.

Fourth, Davy-Songer will continue to comply with all other OSHA rules and regulations concerning blasting and working with explosives. Those procedures include but are not limited to: using a licensed blasting technician, providing proper notification to all authorities before any blasting takes place, guaranteeing that all warning signs, warning whistles, and safety personnel are in place before and during blasting, keeping all explosives in properly ventilated, locked storage magazines unavailable to persons not authorized to handle them, and maintaining an inventory and use record of all explosives.

For all the aforementioned reasons, Davy-Songer's method of conducting its blasting operations during certain non-daylight hours is the safest possible method for conducting the procedure. It is the most effective method of complying with the spirit and purpose of the OSHA regulations -- to enhance employee safety. Davy-Songer, therefore, requests that the Department issue a statement clarifying that the blasting procedure outlined above is not contrary to the standard articulated in 29 CFR 1926.900(j).

If the Department needs any further information in order to process this request, please do not hesitate to call me at the above listed phone number. We can provide any documentation that you may need as well as let you talk to the personnel who are involved in conducting the blasting. We would also welcome the opportunity to meet with you and discuss this matter in person.

Very truly yours,

Kerry E. Saltzman,
For Fox and Grove,