On July 24, 1972, the court ruled that there was a causal relationship between the disease of the plaintiffs and the soot emitted by the factories; the companies were liable as joint culprits; and the companies were guilty of locational and operational negligence. The six companies were jointly ordered to pay total compensation of 88 million yen.
The court's ruling that companies should adopt world-leading technologies and expertise to prevent the discharge of pollutants, at the sacrifice of economic performance if necessary, greatly shook the industrial world in Japan at the time.
Further, the court also blamed the state and local governmentsfor prioritizing economic benefits and not conducting strict assessments of companies (currently termedEnvironmental Impact Assessment) before they were allowed to set up operations in the area.