WASHINGTON (AP) — The Obama administration has delayed a plan to boost safety standards for the type of rail car involved in a deadly explosion in Canada this month.

Officials began work on new rules more than a year before the oil train derailment that killed at least 47 people in Quebec on July 6, but the rules were never finalized. The Pipeline and Hazardous Materials Safety Administration says the rules would fix a dangerous design flaw in rail cars used to haul oil and other hazardous liquids.

They're shaped like soda cans and known as the DOT-111. The cars tend to split open in derailments and other major accidents. The pipeline agency says it needs the delay for "additional coordination" among officials and interested groups.