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Subchapter 4. Construction Safety Orders
Article 5. Rock Drilling

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§1538. Rock Drilling Operations.

(a) When drilling holes in rock, or other dust-producing material, the dust shall be controlled within the maximum acceptable concentrations set forth in Section 5208 (asbestos) and Section 5155 (silica and silicates) of the General Industry Safety Orders. Respiratory protection may be acceptable; refer to Article 4, Sections 1530 and 1531.

(b) All power controlled air drilling shall be performed by use of water or chemical solutions for controlling dust, or other equivalent means.

(c) The ends and each joint of air hoses 1 inch inside diameter or larger shall be chained or secured, as necessary, to prevent whipping in the event of a disconnected hose unless a suitable ball check device or equivalent is provided at the air source.

(d) Air pipe lines shall be protected against accidental impact from vehicles and falling objects at points where breakage of lines would constitute a hazard to employees.

(e) Iron or steel hammers used for removing detachable bits shall be malleable or annealed, so that they will not readily chip or break while being used.

(f) Tugger and anchor lines shall be provided for securing drilling equipment on steep slopes.

(g) Workers shall be provided with, and required to use, personal fall protection as described in Article 24 for all scaling and drilling operations performed on steep slopes. A positive descent control device shall be used for all such applications.

NOTE: See Section 1565(i) for regulation on drilling and loading in the same area. See Section 1696 for requirement for portable compressors.

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Amendment of subsection (a) filed 10-18-77; effective thirtieth day thereafter (Register 77, No. 43).

2. Amendment of subsections (c) and (g) filed 8-13-84; effective thirtieth day thereafter (Register 84, No. 33).

3. Amendment of subsection (g) filed 7-2-98; effective 8-1-98 (Register 98, No. 27).

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