Irving Oil Ltd. is investing $50-million in a series of upgrades at its Saint John refinery. (CBC)

The Irving Oil refinery is undergoing a $50-million maintenance upgrade that will see the hiring of 700 extra workers over the next 12 weeks.

The turnaround project will allow the company to perform maintenance and upgrade work on several units in the refinery’s north and south process areas. 

The Saint John-based oil refinery is the largest in Canada.

The company says roughly 1,000 workers will be directly involved with the project, including 700 tradespeople, such as pipefitters and boilermakers.

Irving Oil also said in a press release that the majority of the new workers are from New Brunswick.  

"This investment will ensure our refinery continues to operate safely, reliably and cleanly," said Mark Sherman, general manager of the Irving Oil refinery in a statement.

"Turnarounds are critical to maintaining the reliability of our refinery’s units, but they’re also important to the broader community through the jobs and spin-offs they bring."