Public Nuisance Dispute Mediation Act Article 19

Several parties sharing common interests in a public nuisance dispute may jointly apply for mediation. During the process of mediation, a third person claiming to share a common interest with an involved party may, upon the approval of the mediation committee, join the ongoing mediation process as a party.The mediation committee shall consider the opinions of the original parties when granting the approval referred to in the foregoing paragraph.
中文原文 公害糾紛處理法第19條
多數有共同利益之公害糾紛當事人,得共同申請調處。
調處事件進行中,主張與當事人之一方有共同利益之第三人,得經調處委員會之許可,加入該調處程序為當事人。
調處委員會為前項許可時,應斟酌當事人之意見。

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