A plumber set off a flare while it was pointed towards a hawker centre, sparking a "huge ball of fire" and a 30-hour police operation involving a total of 65 officers.
Aw Chong Loong, 50, was fined $4,500 yesterday after pleading guilty to committing an act so negligent as to likely cause hurt or injury.
He set off the parachute signal flare, an explosive substance commonly used in marine distress situations, on Sept 26 this year at Block 226C, Ang Mo Kio Avenue 1.
Deputy Public Prosecutor Yang Ziliang said stallholder Tan Yong Joo was seated in front of his fruit stall at the nearby hawker centre at about 4.30pm that day when he heard a loud boom. He turned to his stall and saw a "huge ball of fire about the height of (his) knee" as well as sparks and smoke.
Mr Tan immediately used a long metal rod to get the ball of fire out from his stall, and it wound up under a table in the hawker centre.
A passer-by put out the fire. No one was hurt in the incident.
Witnesses said the pipe-like object flew like a projectile, whizzing and emitting white smoke.
The police were called. During the 30-hour operation, they scoured 23 blocks nearby to find out the cause of the fire.
Aw told police officers he did not see anything, but closed circuit television footage and police checks identified him as a possible suspect. He came clean the next day.
Aw, who operates out of his family's medical hall, had a habit of picking up discarded items to try to make use of them, said DPP Yang.
He was clearing the store at the back of the medical hall that afternoon to make way for a new tenant when he saw a cylindrical object covered with dust on a shelf.
Aw took it outside to have a closer look. Without his glasses, he did not read what was written on it.
He opened a cap on the object and saw a button and a pin attached to a short nylon string.
With the object pointed towards the hawker centre, Aw pulled the string and pin while pressing the button. What followed was a lot of smoke and a whizzing sound.
An alarmed Aw immediately went back into the shop. Meanwhile, a crowd had gathered at the hawker centre and a civil defence fire engine later arrived.
When Aw and his mother walked over to the hawker centre to check out the commotion, he saw that the ground was white, with a piece of tin or metal on the floor. He then realised that this may have resulted from the object he had activated.
The court heard Aw did not own up at first as he did not want people to see him being arrested, or to be known as the one who had set the flare off, sparking a commotion.
Aw, who was unrepresented, could have been jailed for up to one year and/or fined up to $5,000.