Refer to BC Centre of Disease Control Environmental Health Officer.
(http://www.bccdc.ca/our-services/service-areas/environmental-health-services)
At this point, workers should be utilizing the system checker and call 811 to confirm what actions they should be taking, especially when they have a confirmed case of COVID-19 in their home, as they are at high risk of exposure and may be required to self-isolate based on recommendations from 811.
See WorkSafeBC guidance: https://www.worksafebc.com/en/about-us/news-events/announcements/2020/March/covid-19-and-the-workplace
Once a worker has been diagnosed with COVID-19, the public health office will conduct an investigation and will communicate instructions to the employer for what they must do next. As part of their investigation, they will be questioning others in the workplace to identify those who were in close contact with the individual.
If a worker suspects they may be infected, the BC CDC website has a COVID-19 Self-assessment tool (https://covid19.thrive.health/) and depending on the answers, it will provide next steps.