8. DENSO Safety First

The significant catalyst for the establishment of the DENSO ANZEN Standards (DAS) was the explosion accident that occurred on September 8, 1969, at the die-casting factory within the Anjo Plant.

Two blades of the dust collector fan fell off during operation and rubbed violently against the casing. This caused the aluminum dust attached to the blades and casing to become airborne. When the concentration of the dust reached the lower explosive limit, a primary explosion occurred. The explosion stirred up even more aluminum dust, spreading the explosion to other dust collectors. This incident resulted in the death and injury of 12 employees, marking the most severe accident since the company's founding.

The explosion accident had a profound impact on our company, far beyond just a shock. Despite our longstanding emphasis and efforts on plant safety and health, recognized by the “Excellence in Occupational Health Award” from the Minister of Labor in 1961, this accident nullified all our previous efforts.

Investigations by authorities and our internal inquiries revealed that the cause of the explosion was a manufacturing defect in the equipment. However, our major point of reflection was that we were unaware of the explosive potential of aluminum powder. Without knowledge of such dangers, preventive measures cannot be implemented—this was a harsh lesson learned.

In response, a comprehensive inspection of all plants and equipment was conducted, involving specialized teams and external experts. An immediate action taken was the publication of the “Safety Series,” which listed the hazards and inspection items for major materials and equipment, ensuring that this information was disseminated across all workplaces.

On October 14, 1969, the slogan “DENSO Safety First” was established, encapsulating our strong resolve to “never allow such an accident to happen again.” This motto aimed to elevate safety awareness among all employees and promote rigorous safety management.

One year after the explosion accident, a directive from the president reinforced the belief that “all human-made disasters are preventable,” advocating for even more thorough efforts.

To ensure the Anjo explosion accident is never forgotten and to maintain a high level of safety awareness, September 8, the day of the accident, was designated as “DENSO Safety Day.” Each year, on this day, company-wide notifications related to safety are issued, and special safety activities are conducted. Starting from the 2017 fiscal year, the day was expanded to be recognized as “DENSO Group Safety Day,” extending the observance to both domestic and international group companies.