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.

July 20, 2006

Maria Galvan
[by e-mail]

Re: Whether it is mandatory to use a wet saw when cutting brick or concrete block.

Dear Ms. Galvan:

This is in response to your email correspondence dated June 15, 2005, to the Occupational Safety and Health Administration (OSHA). We apologize for the long delay in responding.

We have paraphrased your question as follows:

Question: Do OSHA requirements mandate the use of a wet saw to cut bricks and cement blocks?

Answer: In 29 CFR 1926 subpart Q (Concrete and Masonry Construction), §1926.702(i) contains two requirements regarding masonry saws. It states:

(1) Masonry saws shall be guarded with a semicircular enclosure over the blade.
(2) A method for retaining blade fragments shall be incorporated in the design of the semicircular enclosure.

These requirements address certain safety hazards associated with the use of masonry saws.

One of the problems associated with the use of a masonry saw is that, when used to cut brick, concrete block and masonry, heat build-up and stress can cause portions of the blade to break off and be thrown at a high rate of speed. This is dangerous to both the worker using the saw and employees in the vicinity. Section 1926.702(i) (2) addresses this hazard by requiring "a method for retaining blade fragments" in the mandated enclosure. One of the advantages of using a wet saw is that it reduces the heat build-up and the chances of the blade sections breaking off by cooling the blade with water.1

Another problem associated with cutting these materials is that the dust can be a serious health hazard, as these materials typically contain silica. Exposure to silica dust can lead to silicosis, an irreversible lung disease, and lung cancer. Subpart Q does not address the health hazards associated with the cutting of concrete or brick. These hazards are covered under 29 CFR 1926.55, which states, in part:

(a) Exposure of employees to inhalation, ingestion, skin absorption, or contact with any material or substance at a concentration above those specified in the "Threshold Limit Values of Airborne Contaminants for 1970" of the American Conference of Governmental Industrial Hygienists, shall be avoided.
(b) To achieve compliance with paragraph (a) of this section, administrative or engineering controls must first be implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or other protective measures shall be used ...

Silica is listed in the "Threshold Limit Values" table in §1926.55 (Appendix A). Therefore, with regard to airborne silica, employers engaged in construction are required to ensure their employees are not exposed to levels above the Permissible Exposure Limits listed in §1926.55.

To comply with this requirement, administrative or engineering controls must first be implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or other protective measures must be used to keep the exposure of employees to air contaminants within the prescribed limits.

This standard does not specifically state that a wet saw must be used, but the use of a wet saw for cutting brick, concrete block and masonry is a means of meeting the engineering control requirement in §1926.55(a) with respect to silica dust.2

Some studies have shown that wet cutting methods can reduce average respirable dust levels by up to 94 percent. However, if an employer determines that the use of a wet saw in a particular circumstance is not feasible, and the brick, concrete block or masonry must be cut dry, then the employer would be required to use another engineering control, such as a dust collector, if feasible, or an administrative control. Note that dust collectors alone are typically not sufficient to reduce exposures below permissible limits and employees will usually need to be protected with appropriate respirators as well.3

If you need additional information, please do not hesitate to contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Compliance Assistance, 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.


Noah Connell, Acting Director
Directorate of Construction

1 Note that, whether a wet or dry saw is used, eye and face shields are required under 29 CFR 1926.95(a). [ back to text ]

2For more information on silica, a detailed list of recommendations, and a description of OSHA's Special Emphasis program on silica, go to: http://www.osha.gov/dsg/etools/silica/spec_emph_prog/spec_emph_prog.html.
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3 Because each worker's environment is different, and the amount of occupational exposure to crystalline silica and quartz dust varies, it is typically necessary to make an occupational exposure determination in order to ascertain which respirator is appropriate. The exposure to crystalline silica must not exceed the assigned protection factor of the respirator.
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