The Houston Chronicle published an extensive investigation of worker injuries and fatalities in Texas oil and gas fields, highlighting a lack of federal safety standards protecting onshore drill workers.

From 2007 to 2012, 664 US workers were killed in oil and gas fields, with 40 percent of deaths taking place in Texas. Sixty-five Texas oil and gas workers died in 2012 alone. In that same year, seventy-nine lost limbs, eighty-two were crushed, ninety-two suffered burns and 675 broke bones while working in the fields.

Reporter Lise Olsen finds several factors contributing to these numbers, from oil and gas employers recklessly cutting corners to government inspectors glossing over safety hazards. On top are lax federal regulations that don’t do much to spur improvement. Consider this:

At onshore oil and gas drilling sites, the Occupational Safety and Health Administration is required to investigate only those accidents that kill workers or that cause three or more to be hospitalized. That translated to only about 150 of 18,000 work-related injuries and illnesses in the last six years in Texas. [Emphasis mine]

Olsen shows how under these standards, the details of accidents “remain locked away in confidential company safety reports, insurance archives or remote courthouse files in lawsuits.” She tells the story of a rig collapse that left a drill worker with a broken jaw, cracks in his spine and permanent brain and memory damage. While the well operator (Apache Corp.) settled with the worker in court, OSHA did not investigate the accident because less than three workers required hospitalization.

There’s a lot more in the investigation, which you can read here. The Chronicle will publish a second part this Sunday.