Japan v. Yamamoto

Pneumoconiosis is a disease that involves damage to the respiratory system and that is caused by inhalation of mineral dusts. In 1949, Japan’s government promulgated the Mine Safety Law, which provided measures to protect mine workers. That law granted the minister of international trade and industry (the minister) authority to enact and enforce safety regulations. One form of pneumoconiosis is silicosis, which is caused by silicic-acid dust. In 1950, the minister promulgated safety regulations that required special designation of areas with silicic-acid dust and stringent safety requirements that would minimize inhalation of the dust. However, a study conducted from 1955 to 1957 proved that inhaling any mineral dust, not just silicic-acid dust, could cause pneumoconiosis. Based on that study, in 1960 the legislature promulgated the Pneumoconiosis Law, which emphasized that the government needed to focus on preventive measures in order to curtail instances of pneumoconiosis. One important aspect of the Pneumoconiosis Law was the definition of pneumoconiosis, which broadly encompassed all forms of the disease, including those caused by inhalation of mineral dusts other than silicic-acid dust. When the Pneumoconiosis Law was passed, the safety regulations issued by the minister only vaguely described dust-safety procedures in mines, even though stringent safety measures were available and required in specially designated silicic-acid areas. The more stringent safety regulations were not expanded to include other forms of mineral dust until 1986. In the intervening years, many mine workers were exposed to mineral dusts that led them to develop pneumoconiosis. A group of those workers (plaintiffs) sued the Japanese government (defendant) under Article 1(1) of the National Compensation Law, arguing that the government’s failure to enact and enforce more stringent safety regulations in a timely manner was the cause of their harm. The court of second instance ruled in favor of the harmed workers, holding that it was extremely unreasonable that the government did not revisit the safety regulations for such a long period after the Pneumoconiosis Law was promulgated. The government appealed that decision to the supreme court.