A court convicted a former real estate office manager Tuesday of causing an explosion in Sapporo in 2018 that injured 44 people, and sentenced him to three years in prison, suspended for four years.

The Sapporo District Court handed down the ruling on 35-year-old Takahiro Tsujimoto, a former store manager of an Apaman Co. agency branch in the northern Japan city, after finding him guilty of causing the blast by emptying air freshener cans.

"The defendant emptied many spray cans together with one of his subordinates at a small office despite being aware of the high possibility of a fire being ignited," Presiding Judge Toshikazu Ishida said in giving the sentence.

According to the ruling, Tsujimoto triggered an explosion on Dec. 16, 2018, by turning on a water heater for washing hands in the real estate agency office that was filled with flammable gas after he had emptied around 80 to 90 spray cans there prior to their disposal.

The explosion resulted in damage to eight buildings, injuring 44 people. Tsujimoto also sustained severe injuries.

The spray cans were intended for customers who needed an air freshener for the properties they had rented or purchased. The cans Tsujimoto emptied were part of the unused inventory in the office.

The defendant pleaded guilty at the first hearing of the trial in June, saying "My careless and irresponsible act caused harm to a lot of people. I regret that I did not prevent it by thinking more clearly."

Following the incident, the Environmental Ministry urged municipal governments to inform people about proper ways to dispose of spray cans, such as using up the contents and venting any residual gas outside away from flammable objects.