May 16, 2008

Mr. Gerard Van Der Bas
Sales Representative
Breton USA Customer Service Corporation
1753 Northgate Blvd.
Sarasota, FL 34234

Dear Mr. Van Der Bas:

Thank you for your letter of November 19, 2007, to the Occupational Safety and Health Administration's (OSHA's) Correspondence Control Unit (CCU). Your letter has been forwarded to OSHA's Directorate of Enforcement Programs (DEP) for response. You had concerns related to the guarding of computer numeric control (CNC). Your paraphrased scenario, question, and our response follow.

Question #1: We manufacture CNC contouring machines that use abrasive wheels and abrasive-coated router bits to remove material from stone and engineered stone slabs. The spindle in question rotates up to 6000 rotations per minute (rpm), and we believe the tooling is subject to fracture. Would a machine having no enclosure be considered OSHA compliant?

Answer #1: No. Please note that regardless of whether a machine is provided with guarding by the manufacturer, the employer whose employees are using the equipment must ensure the employees are provided effective protection from flying debris from tools and materials. The use of abrasive wheels in CNC contouring machines is covered by OSHA's Abrasive wheel machinery standard, 29 CFR 1910.215. The standard, at §1910.215(a), provides that "[a]brasive wheels shall be used only on machines provided with safety guards as defined in the following paragraphs of this section . . . . " The standard continues, at §1910.215(a)(2), specifying that the guard must generally cover the spindle end, nut, and flange projections. An exception exists if the work itself provides a suitable measure of protection to the operator. Section 1910.215(a)(2)(i) allows that the guard "may be so constructed that the spindle end, nut, and outer flange are exposed; and where the nature of the work is such as to entirely cover the side of the wheel, the side covers may be omitted." An extreme variability in the location and orientation of the abrasive wheel during CNC operations make it unlikely that the exception will apply in practice.

The use of abrasive-coated router bits in the CNC contouring machine is addressed by OSHA's Machine guarding standard, §1910.212, as opposed to OSHA's Abrasive wheel machinery standard, §1910.215. Part (a)(1) of OSHA's machine guarding standard, 29 CFR 1910.212, broadly addresses the various types of hazards that machines may present. An employer's compliance obligation under this standard also is broadly worded—to provide one or more methods of guarding to protect the operator and other employees in the machine area. An employer, therefore, would be required under 29 CFR 1910.212(a) to evaluate the hazards presented by employee exposure to the abrasive-coater router bits and then use the necessary guarding to provide effective employee protection. Examples of guarding methods include, but are not limited to, barrier guards, two handed tripping devices, electronic safety devices, etc.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. 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. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at 202-693-1850.

Sincerely,



Richard E. Fairfax, Director
Directorate of Enforcement Programs