The number of COVID-19 cases are increasing at the Site C dam site, with 13 active cases now linked to the hydroelectric megaproject, according to BC Hydro.
Spokesperson David Conway says infected and exposed employees have been identified and are isolating.
Some of the cases — 11 of which are related to one another — are believed to have originated in contractors' offices, which have been emptied and disinfected, he said.
"We are taking this situation very seriously," Conway said in an email to CBC.
Some staff are also working from home and monitoring for symptoms, he added.
The Site C dam, the largest infrastructure project undertaken in B.C. history, has been dogged by cost overruns and controversy.
Construction has also been slowed by the pandemic.
As the number of COVID-19 cases rises at the construction site, Conway said there's been regular contact with the Northern Health Authority and contact tracing and containment measures are being taken.
Northern Health has provided advice on how to reconfigure seating on shuttle busses to increase physical distancing between passengers.
The AstraZeneca-Oxford vaccination program on site resumes April 22 for workers over the age of 40. Around 1,430 Site C workers have received at least one dose of vaccine up to this point.
In March, BC Hydro said more than 2,300 workers were expected to be on site by late spring, with additional workers expected in summer.
CBC has contacted WorkSafeBC and Northern Health for comment on the increase in cases on site.