FORT ST. JOHN, B.C. -- The province says clean up at the site of an oil spill in Rolla is now finished.,

According to the B.C. Ministry of Environment, work to clean up the spill has been effective.

The ministry saying minor odour and rainbow sheen could still persist for a few days.

However, the source of the spill remains unknown. A spokesperson for the minsitry saying " Unfortunately, in rare instances, the source of a spill may remain unknown. Spills without a known source or cause can be the result of many varying factors."

Top soil has been removed from a ditch in the East 405 Street area while culverts have been flushed using a hydrovac truck. The spokespersion adding crews "will be in the area frequently to continue to monitor remediation efforts and the situation, until confirmatory samples are received and analyzed" 

The province saying no further updates are expected at this time.