California Code, Public Resources Code - PRC § 15026

(a) On and after July 1, 2002, no person, other than a person licensed pursuant to Article 9 (commencing with Section 4140) of Chapter 9 of Division 2 of the Business and Professions Code, may sell at retail, or otherwise supply, a mercury fever thermometer to a consumer or patient in this state.  A mercury fever thermometer may be sold at retail, or otherwise supplied to a consumer or patient only upon the prescription of a physician, dentist, veterinarian, or podiatrist.  A mercury fever thermometer sold at retail shall be accompanied by clear written instructions concerning careful handling to avoid breakage and proper cleanup should breakage occur.

(b) A violation of subdivision (a) is a violation of the requirements of Chapter 9 (commencing with Section 4000) of Division 2 of the Business and Professions Code and the California State Board of Pharmacy shall enforce the requirements of subdivision (a) in accordance with Chapter 9.