2) Then, there was the rail car theory: A rail car filled with ammonium nitrate, a fertilizer that under the right circumstances can burn and explode, had detonated as a result of the fire and devastated the town. Likening it to a “small nuke,” The New York Post quoted an unnamed Obama administration official as saying: “Authorities suspect the blast was set off by a rail car holding a large quantity of ammonia nitrate that somehow caught fire or blew up.” The Post’s sole source, however, appeared to have been speculating; the source also added that a deliberate act had been ruled out when a criminal investigation by federal and state authorities was, in fact, underway and was no secret. More sourcing might have helped.

In one case, though, an official source confounded the matter. In Texas, five days after the blast, the top environmental enforcer speculated in a public forum that ammonium nitrate in a nearby rail car might be to blame, even though he acknowledged he was not a safety official, nor was his agency part of the investigation. The San Antonio Express-News headline read: “Rail Car Suggested As Cause of Blast.” That same day, investigators quashed the rail car story, telling the press assembled in West that no, the rail car had not exploded; it was itself shredded by the blast.

3) There was also the matter of how much ammonium nitrate was on site the day of the blast, and how much actually exploded. On April 26, NBC and MSNBC reported online that “270 tons of ammonium nitrate exploded at a West, Texas, fertilizer plant last Wednesday.” But 270 tons is the amount of ammonium nitrate that was present at the West facility the previous year, according to its state filing. Precisely how much was on site on the day of the explosion was not revealed by the document, and investigators would later conclude that about one-tenth that quantity—about 28 to 34 tons—actually caught fire and exploded. (There were about 40 tons, total, present in the fertilizer building and another 100 in the railcar on the rail line that did not, in fact, explode.) Other outlets, like The Dallas Morning News and Reuters, were more careful, noting that the filing referred to the prior year while also raising questions about the company’s apparent failure to disclose the quantity to the Department of Homeland Security. The local CBS affiliate did more: before investigators released their initial findings, the station interviewed the facility manager and correctly reported that about 50 tons of fertilizer were present in the building.

4) Some news outlets—often on opinion pages—made sweeping calls for more regulation without clarifying for readers the existing regulations and the company’s compliance with them, the enforcement responsibilities of the patchwork of agencies involved (which agencies had safety responsibilities versus, say, national security or environmental oversight) or acknowledging that industrial accident (preventable or not) was not the only possible explanation. The New York Times ran an op-ed on April 20 that compared the West explosion to the Texas City disaster, which claimed 600 lives in 1947, and threaded them together as consequences of the same “pathological avoidance of oversight.” But ammonium nitrate has been subject to federal regulation and oversight since the 1970s. Elsewhere, explainers from ProPublica and StateImpact, a project of National Public Radio, acknowledged that many facts were still unknown but framed the explosion as a clear regulatory failure. In-state, the Houston Chronicle editorialized that the accident was “entirely preventable.” In a variety of accounts—including this April 29 Christian Science Monitor opinion piece—the EPA (responsible for environmental quality) was conflated without explanation with OSHA (responsible for workplace safety).

With the narrative of preventable industrial accident set, confirmation bias set in. Every past regulatory slip at the West facility was examined as a step on the way to the April 17blast—even though one August 2006 visit by officials led to both a fine and construction of a wall to better protect the anhydrous ammonium tanks. Once again, a local news organization had that detail: WFAA, owned by Belo Corp.

5) Meanwhile, information that ran contrary to that prevailing narrative was sidelined. An April 24 USA Today editorial stated that investigators “seem to have ruled out a deliberate attack” (They had not.). On May 10, that paper’s news pages reported that law enforcement officials had “launched a criminal investigation.” In fact, the blast site had been treated as a possible crime scene all along. The facility was not a factory, as some reported. And fire crews spraying water on the fire did not worsen the explosion as some early reports speculated. You could learn all this by reading the one outlet that was getting it routinely right, The Dallas Morning News.

A strong showing in Dallas

Richard Parker is an award-winning journalist and the author of Lone Star Nation: How Texas Will Transform America, from Pegasus Books. Follow him on Twitter @Richard85Parker.