Cal. Unemp. Ins. Code § 702.6

(a) Any employing unit who is an employer under this division may file with the director a written election to cover, for the purposes of Part 2 (commencing with Section 2601) only, services performed by any of the following:
1. (1) All eligible employees who are a part of a labor organization, provided the election is the result of a negotiated agreement between the employer and the recognized employee organization.
2. (2) All eligible employees in its employ in one or more distinct establishments or places of business who are not part of a labor organization, when the election is requested by a written petition signed by a majority of the eligible employees to be covered by the election.
(b) “Eligible employee,” as used in this section, means an employee who is a California resident whose services are covered under the unemployment compensation laws of another state which does not have a disability insurance program, and who is an “employee,” as defined in Section 13004, for whom the employer complies with the personal income tax withholding provisions of Division 6 (commencing with Section 13000).
(c) Upon the filing of an election, the filing entity shall, upon approval by the director, become an employer subject to Part 2 (commencing with Section 2601) to the same extent as other employers, and services performed by its employees who are subject to the election shall be deemed to constitute employment subject to that part. Sections 704, 707, 986, and 2903 shall apply to elections under this section.