As part of a plea deal, Mr Spinelli pleaded guilty to the charge on Thursday and will only have to pay $120 of his hefty $620 fine up front as long as he commits no other offences.
“Based on the facts, at the conclusion of the investigation, we feel that the charge and the disposition were appropriate,” Kingston police said in a statement.
“We are very thankful no one was injured during the gender reveal incident and sympathetic to the fact it startled the community.”
In April, police in Kingston received reports of a loud explosion and tracked the incident to Torromeo quarry, where people admitted to holding a gender reveal party.
Around 80 pounds (36 kilograms) of Tannerite, an explosive sold over the counter for firearms practice, had been detonated, police said.
Some nearby residents reported their homes were shaken by the explosion. No injuries were reported as a result of the reveal, police said.
While the family purportedly said they thought the quarry would be the safest place to blow up the explosive authorities had alleged that Mr Spinelli "caused public alarm” with the antics.
Similar gender reveal stunts have been known to have gone dangerously awry in the past, leading to deadly incidents and even wildfires.
In February, an expectant father in New York tragically died after he attempted to build an explosive prop for a gender reveal party which then accidentally detonated.
In September 2020, a “smoke-generating pyrotechnic device” intended for a similar reveal ignited a wildfire in Southern California, burning down acres of land.
It was not immediately clear if Mr Spinelli had a lawyer available to comment on his behalf.
Additional reporting by the Associated Press
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