More than 150 workers at a steel plant in Arnprior went on strike Wednesday morning after talks between management and the Canadian Auto Workers broke off just before midnight Tuesday.

The CAW union and Sandvik Materials Technology Canada have been negotiating since June 15 — the workers' collective agreement expired July 1.

"We were informed by [management] that it appeared we weren't going to get an agreement," CAW representative Derek Mosley told assembled workers Wednesday morning.

His announcement was greeted with silence.

"So we at the time made the decision to notify the members at the plant to leave," Mosley said.

The Swedish-based multinational company has plants across Canada and around the world. The Arnprior plant makes steel tubing for the nuclear, aerospace and automotive industries.

Gary Riopelle, 63, came to work for his regular shift Wednesday morning. Instead, he placed a picket sign around his neck.

Riopelle has worked at the plant for 35 years, and it's the first time he's been on strike.

"We can't make concessions. I worked all my life for a pension, and they want to take my pension away from me," Riopelle said.

The CAW union says the steel plant's managers also want to scale back cost-of-living wages.

In an emailed statement sent to CBC News Wednesday night, Sandvik wrote: "The company hopes that an early resolution can be reached. With that said, the union’s current, reduced demands, will increase the company’s labour costs by a minimum of six per cent a year for three years in a row. This is something that simply cannot be sustained in light of the state of manufacturing in Canada."