A California drifter left the parts to build an “improvised explosive device” at a busy eatery in the Port Authority Bus Terminal — hiding them in a piece of luggage, officials said Thursday.

Arsenio Mason, 39, a fugitive from the Golden State, allegedly planted the bag on the first floor of the terminal’s south wing inside Deli Plus around 5:15 p.m. Wednesday.

A PAPD K-9 unit inspected the suitcase, didn’t detect explosives and brought it to a police substation at the terminal to examine it, police sources said.

Inside, officers found what appeared to be a disassembled improvised explosive device along with a knife, bolt cutters and screwdrivers, the sources added. They also found personal hygiene items in the bag.

Prosecutors said in court Thursday the PAPD turned the suitcase over to the NYPD’s Bomb Squad, which detonated it at Rodman’s Neck in The Bronx by applying heat,

But an official with the Manhattan District Attorney’s Office later said that the device was not detonated and that there may have been a miscommunication. The office plans to update Mason’s attorney and the court, the official said.

The NYPD also said the device wasn’t detonated.

“This was not fully assembled,” NYPD Deputy Commissioner John Miller said, adding that the powder was believed to be “a low-order explosive of some kind.”

Cops arrested Mason when he returned to the terminal around 8 p.m. and said he was looking for his briefcase, a criminal complaint said.

He was charged with reckless endangerment, criminal possession of a weapon, possession of burglary tools and criminal possession of a controlled substance, PAPD officials said.

A police source said the device “appears to be a dismantled flash bang or what they would call a distraction device” and that it could have been reassembled to be an explosive device.

Mason, a California native, is considered a fugitive after he violated parole in his home state before heading east.

Judge Herb Moses set bail at $500,000 but ordered Mason automatically remanded on account of his fugitive status.

Mason has a criminal record in Oregon, Alaska and Washington State, prosecutors said. The charges against him included drug possession, stolen property, bad checks and trespassing, a police source said.

Additional reporting by Amanda Woods