'The Office' stars are paying tribute to actor Mark York after news of his death

• "The Office" stars are paying tribute to guest actor Mark York.
• York played Billy Merchant, properties manager of Dunder Mifflin Scranton building.
• Rainn Wilson called York "terrific" and "dynamic" after news broke of York's death at 55.

"The Office" stars are reacting to news of actor Mark York's death. York guest-starred as Billy Merchant in several episodes of the beloved NBC sitcom over the course of multiple seasons.

York's costars started paying tribute to him on social media after an obituary written by his family shared that York had died in Dayton, Ohio, on May 19 after "a brief and unexpected illness," at age 55.

The coroner's office in Montgomery County (where Dayton is located) confirmed to the New York Times on Monday that York had died of natural causes.

Though his cameos were brief, York left a lasting impression on "The Office" viewers with his to-the-point responses to Dunder Mifflin regional manager Michael Scott's ignorant comments, usually about Billy using a wheelchair.

Billy, who was a paraplegic like York, was the properties manager of the building where Dunder Mifflin's Scranton branch was located, and he rarely had any patience for Michael's nonsense.

For example, in a memorable episode titled "Casino Night," Michael assumes that the woman next to Billy is his nurse.

"She was never my nurse, I met her at Chili's. She was my waitress," Billy told Michael in the scene, setting the record straight.

Billy appears in a total of four episodes in the sitcom (that ran for nine seasons, from 2005 to 2013) and is mentioned in a few other instances.

Aside from his memorable stint as Billy, York also had guest roles in TV shows like "8 Simple Rules" and "CSI: New York."

York is survived by his parents, Becky and Glenn York, and his brothers, Jeff, David, and Brian.

York's costars spoke warmly about working with him on 'The Office' in their social-media tributes

In four episodes across the first five seasons, "The Office" viewers watched Billy help Michael fundraise $340 for rabies research, assist the clueless regional manager in finding new office space after Michael briefly leaves Dunder Mifflin, and leave midway through an offensive disability-awareness meeting.

After news broke of York's death, Rainn Wilson, who played Michael's sidekick and assistant Dwight Schrute, tweeted that York was a "terrific human" and "a dynamic actor."

Jenna Fischer, who played Pam Beesly-Halpert, also wrote in a tweet it was "a pleasure to work with" York while sending love to his family.

Angela Kinsey, who played Pam's "The Office" nemesis (also named Angela), tweeted that she was "very sad to hear about Mark's passing."

The obituary by York's family echoed Wilson's, Fischer's, and Kingsey's sentiments and spoke to York's "many travel opportunities and many dreams for the future."

"He had such an outgoing, uplifting, positive attitude and personality. He always tried to look at what he could accomplish and do, not what he couldn't do," the obituary read, adding that York had been a paraplegic since 1988.

According to The Times report about his death, York used his roles on-screen to promote visibility for wheelchair users. He also supported doctors and researchers trying to find a cure for spinal-cord injuries and served as a representative for SCI Research Advancement, a group trying to fund research for spinal cord regeneration.

"As an actor, he's attempting to open the minds of casting directors, and others in Hollywood, to also see a wheelchair-user in real-life roles such as doctors, lawyers, businessmen, and such, because...well, they are," York's website said about his work in Hollywood.

York's obituary also shared that in recent years before his death, he had also been working as an inventor and had successfully secured two patents for his inventions.