Two people are dead following a construction accident Tuesday morning at a fracking sand storage and shipping facility in northwestern Alberta.

Occupational Health and Safety is investigating the workplace incident which took place at a Source Energy Services terminal facility south of Fox Creek.

An OHS investigator was dispatched to the scene, about 260 kilometres northwest of Edmonton, Tuesday afternoon.

The workers, both contractors, were killed during the construction of additional storage at the terminal, a spokesperson with Source Energy said.

"Source is working with all parties at this time and fully cooperating with the ongoing investigation," the Calgary-based company said in an emailed statement.

"Our thoughts are with the family, friends, and coworkers of the deceased during this tragic time. Source has dispatched emergency counselling services for those immediately impacted and extended further access to counselling services to families of the workers."

OHS is expected to release further details on the incident by Wednesday afternoon.

RCMP are investigating and the site has been shut down.

Fracking sand is used by companies in Alberta's energy sector to extract oil and natural gas from tight geologic formations.