An explosion at Nexen's Long Lake Plant in northern Alberta has left one person dead and another critically injured, according to police.

The blast took place at around 3:20 p.m. local time on Friday after which the plant activated its emergency response plan and deployed both fire and medical crews to the site. Personnel including first responders from teh Regional Municipality of Wood Buffalo attended the scene and RCMP arrived at 5 pm. The plant is located near Fort McMurray.

"We are deeply saddened to confirm one fatality and a second person is at hospital. All other personnel are accounted for. The affected facility has been shut down and we are stabilizing the scene. There is no immediate danger to the neighbouring communities or personnel still on site. Regulators have been notified," stated a release on Nexen's website.

Alberta's provincial regulator, AER (Alberta Energy Regulator), tweeted that it was "responding" to the situation and more information would be provided as it becomes available.

Premier Rachel Notley echoed MLA Shaye Anderson's sorrow for the victims by retweeting him on social media.

Horrible news. Heart goes out to family and friends. @BrianJeanWRP @TanyYao positive thoughts to all affected.

— shaye anderson (@sandersonNDP) January 16, 2016

Last September, Nexen Energy — a wholly-owned subsidiary of China's state-owned CNOOC — announced it is shutting down its Long Lake oilsands operations south of Fort McMurray in response to an emergency regulatory order.

The AER was investigating the Nexen Long Lake plant last year as part of an ongoing probe into a large spill discovered in July, in which five million litres of of bitumen, sand and oil had leaked from a pipeline. Nexen was permitted to partially resume operations last September.

This is a developing story. Please check back for updates.