After retrocession, the Taiwan Metals Mining Corporation set up a copper smelting plant here, and explosives were used to dig up the minerals, causing the "Yin Yang Sea" to spread and become increasingly turgid and contaminated. Thirteen years ago, all work was stopped there thanks to the intervention of environmentalists, but the Yin Yang Sea is still finding it hard to recover.
光復後，台灣金屬礦業公司在此設煉銅廠，在利用爆破採礦後，陰陽海的面積與濁度越來越大；儘管後來因環保人士抗爭已經停工至今十三年，但陰陽海仍難清澈。