Occupational Safety and Health Act Article 28

If two or more business entities contribute fund jointly for a contracted operation, they shall select one person to act as the representative. Said representative is deemed the employers of such operation, and is liable for the prevention of occupational accidents as stipulated for employers’ under the Act.
中文原文 職業安全衛生法第28條
二個以上之事業單位分別出資共同承攬工程時,應互推一人為代表人;該代表人視為該工程之事業雇主,負本法雇主防止職業災害之責任。

English translation for reference only; the Chinese text prevails. Not legal advice.