Fuelfix.com reports that oil company bankruptcies surged over the past two months as drillers ran into hefty interest payments amid one of the toughest financial squeezes for the industry in decades.

The news and energy site, anchored by business reporters at the Houston Chronicle, the San Antonio Express-News and other Hearst newspapers, reported that 18 North American oil companies filed for bankruptcy in March and April, a big two-month haul that included two of Houston’s midsized public drillers, Energy XXI and Ultra Petroleum Corp.

Several of the 18 producers chose not to make quarterly interest payments on a combined $8.9 billion in debt while banks cut oil company credit lines, part of a semi-annual review by lenders.

Read the Fuelfix.com story here and Forbes’ list of the 15 biggest oil bankruptcies so far here.