On November 10, 2020, at a warehouse in Sisa-cho Uradome, Matsuura City, Shiraishi Construction Co., Ltd. failed to implement necessary safety measures, such as installing walk boards wider than 30 centimeters and setting up safety nets, during roofing work. As a result, a worker fell through a slate roof, approximately 6.3 meters onto a concrete floor, and died. The company and the head of its housing division were each issued a summary order of a 300,000 yen fine for violations of the Labor Safety and Health Act, with their penalties confirmed on July 30, 2021. This incident constitutes a violation under Article 28, Paragraph 1, Item 3 of the Construction Business Act, and is subject to supervisory measures. The prefectural government of Nagasaki issued an instruction on September 17, 2021, requiring the company to take measures to prevent recurrence, including compliance with relevant laws and strengthening safety management systems, and to report these measures in writing promptly.