Occidental debt ratings were slightly lowered.

In lowering the ratings, Fitch Investors Service said it acted “in view of the increased uncertainty in Occidental’s operating environment,” meaning the recent collapse of oil prices. The action affects four senior debt issues totaling $1.9 billion, but Occidental Petroleum’s commercial paper rating was affirmed as “very good.” Fitch said Occidental’s recent acquisition of Midcon, a large Chicago-based pipeline company, should strengthen the company despite the new debt that it took on in the process.