Oil-train records held by the Texas Department of Public Safety are not exempt from state open records law, the state attorney general ruled last week, and must be released in full to news organizations.

Kansas City Southern Railway had argued that releasing the information to the public would compromise security and customer confidentiality, and help the railroad’s competitors.

In a letter dated Thursday, the attorney general’s office dismissed those arguments and said the state “must release the submitted information.”

McClatchy requested information about crude-oil trains from more than 20 states, including Texas, last year in an effort to track the potential dangers from oil shipments, which have skyrocketed from fewer than 10,000 trains in 2008 to more than 500,000 last year as U.S. production of crude oil from fracking boomed.

Railroads initially asked state officials to keep the information confidential and limit its disclosure to local emergency responders, but most of the states ultimately agreed to make the documents public. One notable exception is West Virginia, where a crude-oil train derailed and exploded Monday.

In October, the Federal Railroad Administration issued guidance that the reports, which show the estimated number of trains per week and their routes, were not sensitive to either commercial interests or security. In its letter, the Texas attorney general’s office agreed that the companies offered no evidence to support their claims that releasing the information would hurt their businesses.

The U.S. Department of Transportation began requiring railroads to report large shipments of Bakken crude oil from North Dakota to other states last May, after the derailment of a CSX train in Lynchburg, Va., that resulted in a spill, fire and evacuation. The derailment this week near Mount Carbon, W.Va., also on a CSX rail line, resulted in a fire that burned for four days and kept more than 100 residents out of their homes. All but a few were allowed to return Friday.

Records McClatchy obtained from Missouri and Kansas show that Kansas City Southern told those states it planned to operate one to five oil trains a week between Kansas City, Mo., and Nederland, Texas. A map that accompanied the documents showed that the trains would pass through Missouri, Kansas, Oklahoma, Arkansas, Louisiana and Texas.

In July, CSX and Norfolk Southern sued the Maryland Department of the Environment to block the release of oil-train information the state was planning to release to McClatchy and the Associated Press. A trial is scheduled for April.

The Pennsylvania Office of Open Records ordered that state to release its records in October after McClatchy and two Pittsburgh newspapers appealed a state agency’s July decision to withhold them.