Rio Tinto smelter workers go on strike in Kitimat, B.C.

Approximately 900 Rio Tinto workers at the company's aluminum smelting facilities in Kitimat, B.C.,have gone on strike.

The walkout began on Sunday, at one minute after midnight. Unifor Local 2301, which represents the workers, had issued a 72-hour strike notice after nearly seven weeks of negotiations.

Jerry Dias, Unifor'snational president, saidthe strike comes down to what he calls"Rio Tinto's greed and lack of respect'' for the union members working at the Kitimat smelting facilities.

The union says it has proposed the first changes to workers' retirement income and benefit levels in more than a decade, including moving younger workers to defined benefit from defined contribution pension plans.

It also says negotiations have focused on a backlog of more than 300 grievances resulting from the company's use of contractors and its refusal to hire full-time workers.

Bargaining had continued up until the strike deadline. The company said Sundayit "has made every effort to reach a mutually beneficial agreement" and will continue to do so.

A Rio Tinto spokesperson said the smelter and powerhouse continue to operate, with staff and employees working under an essential services order granted by the B.C. Labour Relations Board.

"Rio Tinto is currently assessing how this will affect aluminum production and will work closely with customers, employees and the community to limit disruptions," the spokesperson wrote in an email to CBC News.