Howard Berkes

Updated at 4:50 p.m. ET

Investigators in Las Vegas are sifting through evidence they've gathered from the homes of the man who sprayed a concert crowd with gunfire. They've begun to interview his girlfriend. They've learned quite a bit about Stephen Paddock's past and preparation, but there is still no explanation for why he damaged and destroyed so many lives.

The second-highest ranking member of the Florida Senate pledged a legislative review of a state law that has allowed injured undocumented workers to be arrested and potentially deported rather than paid workers' compensation benefits.

"Legitimate injuries shouldn't be denied just because the person was an undocumented immigrant," said Republican Sen. Anitere Flores, the president pro tempore of the state Senate and chairwoman of the Banking and Insurance Committee.

At age 31, Nixon Arias cut a profile similar to many unauthorized immigrants in the United States. A native of Honduras, he had been in the country for more than a decade and had worked off and on for a landscaping company for nine years. The money he earned went to building a future for his family in Pensacola, Fla. His Facebook page was filled with photos of fishing and other moments with his three boys, ages 3, 7 and 8.

But in November 2013, that life began to unravel.

NPR's ongoing investigation of the advanced stage of the fatal lung disease that afflicts coal miners has identified an additional 1,000 cases in Appalachia.

That brings the NPR count of progressive massive fibrosis, the most serious stage of the disease known as black lung, to nearly 2,000 cases in the region, all of which were diagnosed since 2010.

Former Massey Energy CEO Don Blankenship is marking his release from federal custody with an appeal for vindication by the U.S. Supreme Court.

Blankenship served a one-year federal prison sentence after being convicted of conspiracy to violate federal mine safety laws. The charges stemmed from the disaster at a Massey Energy mine in West Virginia in 2010 that left 29 coal miners dead.

Updated at 6:25 p.m. ET

Two Democratic members of Congress want three federal agencies to work together to get a more accurate count of coal miners suffering from progressive massive fibrosis, the worst stage of the fatal disease known as black lung.

The request is a response to an NPR investigation that shows 10 times as many cases of the advanced stage of black lung as identified and reported by the National Institute for Occupational Safety and Health.

Across Appalachia, coal miners are suffering from the most serious form of the deadly mining disease black lung in numbers more than 10 times what federal regulators report, an NPR investigation has found.

The government, through the National Institute for Occupational Safety and Health, reported 99 cases of "complicated" black lung, or progressive massive fibrosis, throughout the country the last five years.

West Virginia's Democratic candidate for governor is a billionaire, a philanthropist and a resort and coal mine owner who cites his business and mining experience as major attributes as he seeks to lead his home state out of a severe budget and economic crisis.

"I am not a career politician; I am a career businessman," wrote Jim Justice in an April 5 op-ed that appeared in the Charleston Gazette-Mail.

A "race to the bottom" in state workers' compensation laws has the Labor Department calling for "exploration" of federal oversight and federal minimum benefits.

"Working people are at great risk of falling into poverty," the agency says in a new report on changes in state workers' comp laws. Those changes have resulted in "the failure of state workers' compensation systems to provide [injured workers] with adequate benefits."

Injured workers face "inherent conflict of interest," barriers to benefits, "unequal treatment," limited appeals and little to no independent oversight when employers opt out of state-regulated workers' compensation, according to a new study.

An injured worker featured in an NPR/ProPublica investigation of the opt-out alternative to workers' compensation has settled with the company that denied her medical care and wage-replacement payments after an incident at work.

U.S. Department of Labor Secretary Thomas Perez says his agency will use its "bully pulpit" to strike at what he calls "a disturbing trend" that leaves workers without medical care and wage replacement payments when they are injured on the job.

In an interview with NPR, Perez also confirms a Labor Department investigation of an opt-out alternative to state-regulated workers' compensation that has saved employers millions of dollars but that he says is "undermining that basic bargain" for American workers.

An Oklahoma law that lets employers opt out of state-regulated workers' compensation has been rejected and declared unconstitutional by state regulators.

The Oklahoma Workers' Compensation Commission called the alternative workplace-benefit plans that some employers adopted under the law "a water mirage on the highway that disappears upon closer inspection."

The unanimous ruling by the commission, issued Friday, is expected to be appealed.

Thirty years ago, as the nation mourned the loss of seven astronauts on the space shuttle Challenger, Bob Ebeling was steeped in his own deep grief.

The night before the launch, Ebeling and four other engineers at NASA contractor Morton Thiokol had tried to stop the launch. Their managers and NASA overruled them.

That night, he told his wife, Darlene, "It's going to blow up."

Kevin Schiller had no idea what hit him.

With 21 years on the job, the building engineer for Macy's department stores had been in and out of every nook and cranny of many of the retail giant's Texas stores, including the storage room in the Macy's in Denton, Texas.

One minute, the stocky, 6-foot-2 Schiller was searching there for a floor drain. The next, he was sprawled on the floor, stunned, confused and bleeding slightly.

Updated 7:30 p.m. ET with Kline comment

Ten ranking Democrats on key Senate and House committees are urging the Labor Department to respond to a "pattern of detrimental changes in state workers' compensation laws" that have reduced protections and benefits for injured workers over the past decade.

As states consider allowing employers to completely opt out of workers' compensation plans, NPR and ProPublica take a look at how the concept has worked in Texas. Read the full investigation here.

Billy Doyle Walker loved working in the sky. He used to say he could see forever, perched high up communications towers as he applied fresh paint.

Three years ago, working halfway up a 300-foot steel tower at the LBJ Ranch, the panoramic view included the rolling green hills and meadows of the Texas Hill Country. The tower was used by former President Lyndon B. Johnson to communicate with the White House.

The nation's coal miners have lost an advocate — a pulmonologist who helped create a national movement in the 1960's that focused national attention on the deadly coal miners' disease known as black lung.

Dr. Donald Rasmussen died July 23 at age 87 in Beckley, W.V., where he spent close to 50 years assessing, studying and treating coal miners — more than 40,000 of them, by his account. His work documenting the occurrence of black lung helped trigger a statewide miners strike in West Virginia in 1969.

The inspector general of the Labor Department is conducting an audit of the Mine Safety and Health Administration's handling of delinquent mine safety penalties.

The tattoos on Dennis Whedbee's left arm describe what he lost when the North Dakota oil rig where he was working blew out in 2012. There's an image of a severed hand spurting blood, framed by the word "LOST" in block letters and the date: "9-23-12."

The message underscores Whedbee's frustration with a workers' compensation system in which benefits and access to benefits have changed in North Dakota and across the country.

"I lost a hand at work and this is workman's comp," Whedbee, 53, says at his home in Pennsylvania. "Give me what I deserve. I deserve a hand."

Federal lawmakers have revived a mine safety reform bill that addresses a regulatory failure detailed in a joint investigation by NPR and Mine Safety and Health News.

The Robert C. Byrd Mine Safety Protection Act includes a provision that directly addresses the Mine Safety and Health Administration's (MSHA) failure to fully enforce penalties for safety violations at the nation's mines.

Frances Stevens could have been a contender. She was training to be a Golden Gloves boxer and working as a magazine publisher in 1997 when 1,000 copies of the latest issue arrived at her San Francisco office.

"I'd just turned 30. I was an athlete. I had a job that I loved, a life that I loved," she recalls. "And in a second my life changed."

Six weeks before a landmark mine disaster trial, federal prosecutors in West Virginia have added a new allegation to the criminal conspiracy charges lodged against former Massey Energy CEO Don Blankenship.

At the time of their accidents, Jeremy Lewis was 27, Josh Potter 25.

The men lived within 75 miles of each other. Both were married with two children about the same age. Both even had tattoos of their children's names.

Their injuries, suffered on the job at Southern industrial plants, were remarkably similar, too. Each man lost a portion of his left arm in a machinery accident.

A federal appeals court has vacated a sweeping gag order in the criminal case involving former Massey Energy CEO Don Blankenship and the 2010 Upper Big Branch coal mine disaster.

Workers injured on the job are supposed to get guaranteed medical care and money to live on. Employers and their insurance companies pay for that.

And in return, employers don't get sued for workplace accidents. But this "grand bargain," as it's called, in workers' compensation, seems to be unraveling.

A few hours after ProPublica and NPR issued the first in a series of reports about workers' compensation "reforms" sweeping the country, the Occupational Safety and Health Administration coincidentally released a paper linking workplace injuries to income inequality.

Dennis Whedbee's crew was rushing to prepare an oil well for pumping on the Sweet Grass Woman lease site, a speck of dusty plains rich with crude in Mandaree, N.D.

It was getting late that September afternoon in 2012. Whedbee, a 50-year-old derrick hand, was helping another worker remove a pipe fitting on top of the well when it suddenly blew.

Two weeks after NPR and Mine Safety and Health News reported nearly $70 million in delinquent mine safety penalties at more than 4,000 coal and mineral mines, federal regulators suddenly revived a rare approach to force mines to pay.

They cited a delinquent coal mine for failing to pay $30,000 in overdue penalties and gave the mine's owner two weeks to pay. He didn't, so the Mine Safety and Health Administration (MSHA) shut down the mine. Within 40 minutes, mine officials agreed to a payment plan and the mine reopened.

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