Reuters reported that refinery incidents in the US and Canada have contributed to a drop in Canadian heavy oil prices by heightening the effects of an already oversupplied market.

As quoted in the market news:

Western Canada Select heavy blend for June delivery last sold for $19.25 a barrel under benchmark West Texas Intermediate, compared with $17.50 under on Tuesday.

The spread on WCS has widened by $4.20 since last Friday, when it appeared that seasonal demand for asphalt was driving down the discount.

Click here to read the full Reuters report.