California Code, Health and Safety Code - HSC § 119325

(a) The piercing of the ear with a mechanical stud and clasp device does not constitute body art or body piercing as defined in this chapter. It is the intent of the Legislature, in enacting this article, to provide uniform and statewide requirements for the performance of ear piercing with a mechanical stud and clasp device. The piercing of an ear with a mechanical stud and clasp device shall only be subject to the requirements in this article.

(b) The area within a facility where mechanical stud and clasp ear piercing is conducted shall be safe and sanitary and shall not constitute a threat to the public health and safety, as reasonably determined by the local enforcement agency.

(c) The mechanical stud and clasp device that is used to pierce an ear pursuant to this article shall be single-use, presterilized, stud and clasp only.

(d) The single-use mechanical stud and clasp device used to pierce an ear pursuant to this article shall meet the jewelry requirements in subdivision (e).

(e) Only jewelry made of ASTM F138, ISO 5832-1, and AISI 316L or AISI 316LVM implant grade stainless steel, solid 14-karat through 18-karat yellow or white gold, niobium, ASTM F136 6A4V titanium, platinum, or other materials found to be equally biocompatible shall be placed in newly pierced skin.