Lu Chung-chi, owner of Colour Play Asia, was behind the event at Formosa Fun Coast where coloured corn starch being sprayed on partygoers ignited under the heat of stage lights last June, sending them running for their lives and leaving hundreds injured.
He was found guilty of negligence causing death at Taipei's Shihlin district court as relatives of the victims gathered outside waving banners calling for justice.
A press statement from the court released after the verdict paid tribute to the young victims of the tragedy.
"Most of the victims were very young and their wonderful lives were about to start. They had beautiful dreams to be realised," it said.
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"Because of the explosion, 15 of them lost their lives and most of the survivors suffer tremendous physical and emotional pain and torment.
"Relatives of the deceased suddenly lost their family members and suffered irreparable and excruciating pain and regret," it added.
The case has angered grieving relatives and the families of the injured as only Lu was indicted over the disaster. He was one of nine people investigated, including the chairman and president of the water park.
Campaigners have urged prosecutors to open a new investigation into the accident, with a group of 50 rallying outside court today, waving banners saying: "Return Justice and Fairness to Me".
Some said they were pleased with the verdict, but that the sentence was not long enough. The charge of negligence leading to death carries a maximum sentence of five years.
The high prosecutors' office told AFP today it had ordered a district court to reopen the investigation into the other eight originally investigated.
Almost 500 partygoers were injured in the blast, more than 200 of them seriously. Horrific video footage showed revellers - most of them between 18 and 25-years-old - screaming as they tried to escape.