An insurer shall not insure an employer against his liability for additional compensation arising out of injuries to illegally employed persons under 16 years of age, as provided for by Part 4 (commencing with Section 1171) of Division 2 of the Labor Code.
Source:
Section 11661.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=INS§ionNum=11661.5..