The Appellate Division panel upheld a lower court decision Monday dismissing a lawsuit filed by the firefighter, Raymond Johns.
Johns was on the toilet at the firehouse on Nov. 27, 2015 when, he said, he felt a small explosion.
Examining himself, he said he discovered a bleeding blister on his scrotum.
On the toilet seat, Johns said he found the remnants of a bang snap -- a small firework that detonates when compressed.
Johns sued fellow firefighter Thomas Wengerter, who admitted to placing the snaps elsewhere in the firehouse as a joke but denied placing the snaps that injured Johns.
Wengerter was suspended.
Johns, who suffered a minor burn, returned to work a little more than a week later.
A Superior Court judge dismissed the claim two years ago, finding that Wengerter did not intend to harm Johns.
Because the incident involved "horseplay" in the workplace, Johns was potentially entitled to workman's compensation but not to sue, the judge ruled.
The appeals court affirmed both findings Monday.
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