Just before midnight on Sunday, 10th December, a 54-year-old man spied a single cockroach in his Kumamoto apartment.
In response, he hastily doused the proximity with insecticide. By early morning, the balcony window had been blown off his residence. The man himself was laid up with minor injuries. As for the cockroach, little is known.
Kumamoto Higashi Police told the Mainichi Shimbun, in a statement released the following day, that the explosion occurred just minutes after the insecticide application. Burn marks were found next to the man’s kotatsu, a Japanese self-heating table. The National Consumer Affairs Centre of Japan states that the incident is one of many reported fires and explosions, caused by flammable insecticide entering electrical outlets. The authorities stress that the man’s injuries were only slight.
Cockroaches have been a prolific pest since Japan’s Neolithic period. In a 2022 study for Kumamoto University, Professor Hiroki Obata identified cockroach egg impressions on 5,000-year-old Jomon earthenware.
Around 16mm long, the insects generally rest in dark, humid spots in the daytime and search for food at night. Top indoor locations include kitchen sinks, cracks and corners of cupboards, pipes, and bathroom furniture.
Cockroaches destroy possessions and even threaten Salmonella and Hepatitis. Their oily excrement not only has ‘an offensive and sickening odor’ but triggers rashes, allergic reactions and asthma attacks.
It is no wonder that the afflicted man rushed to rid his property of such a hazardous visitor.
Less than 40 miles from two national parks and set on the banks of the Shirakawa River, Kumamoto is a popular locale for pesky bugs. On December 10th, it enjoyed sunny, rain-free weather of 7°C.
Insecticide sprays are a controversial method of cockroach extermination. Pest-management specialist Philip Koehler states that ‘using chemicals alone can result in insecticide resistance and, ultimately, very poor control.’ Most products are also highly flammable, especially when discharged near electrical outlets. In this week’s case, police credit an electric kotatsu with starting the explosion.
The exact brand of insecticide used by the man is undisclosed. Several insect-killing sprays are available in Japan, costing anywhere from 712 yen (5 USD) to 1280 yen (9 USD) on Rakuten or Amazon. A current best-seller is the ゴキジェット (Gokijet) insecticide. When sprayed directly at a cockroach, the product smothers the insect within a suffocating bubble.
Insecticide-induced explosions are hardly an unprecedented phenomenon. In 2017, a 13-year-old boy destroyed six apartment units trying to kill a bedbug in Cincinnati, Ohio. Associated damages totaled $300,000.
Integrated Pest Management (IPM) is generally considered the most effective and environmentally sensitive way of getting rid of cockroaches. As described by the United States Environmental Protection Agency, the method involves identifying, controlling, and preventing pests. Typically, this means clearing clutter, cleaning surfaces, heat/cold treatments and installing insect barriers. Koehler recommends pursuing IPM yourself or through a professional pest control service.
The tale of the anonymous man and his insect nemesis has now garnered considerable media attention, traveling from regional news outlets to WION and the New York Times. An X-user has even announced a worldwide ‘cockroach’s week’ (sic.) after a Grand Koti Hotel customer recently spotted a dead cockroach in his fish biryani. See the related Reddit chain here.
All in all, one can only hope that the injured man and offended diner make speedy recoveries.
