29 CFR 1917.93: Head protection.

(a) The employer shall ensure that each affected employee wears a protective helmet when working in areas where there is a potential for injury to the head from falling objects.

(b)(1) The employer must ensure that head protection complies with any of the following consensus standards:

(i) American National Standards Institute (ANSI) Z89.1-2009, “American National Standard for Industrial Head Protection,” incorporated by reference in § 1917.3;

(ii) American National Standards Institute (ANSI) Z89.1-2003, “American National Standard for Industrial Head Protection,” incorporated by reference in § 1917.3; or

(iii) American National Standards Institute (ANSI) Z89.1-1997, “American National Standard for Personnel Protection—Protective Headwear for Industrial Workers—Requirements,” incorporated by reference in § 1917.3.

(2) Head protection devices that the employer demonstrates are at least as effective as head protection devices that are constructed in accordance with one of the above consensus standards will be deemed to be in compliance with the requirements of this section.

(c) Protective hats previously worn shall be cleaned and disinfected before issuance by the employer to another employee.