Former Massey Energy CEO Don Blankenship was released from prison Wednesday after serving a one year sentence in connection with the April 2010 explosion at the Upper Big Branch mine in West Virginia, which killed 29 coal miners. The Upper Big Branch blast was the worst US mine disaster in 40 years.

Blankenship served the first ten months of his sentence at the Taft Correctional Institution in Southern California. The facility, which houses many white collar criminals, boasts baseball diamonds and soccer fields along with tennis and racquetball courts. Blankenship was then moved to a halfway house for a month and spent the last month prior to his official release at his home in Las Vegas.

In tweets Blankenship posted after his release, the millionaire coal boss showed no remorse for the deaths of 29 miners. He complained that at Taft he had to return to his room several times a day to be counted and could not choose what to watch on TV.

“Not being able to go anywhere off a 4-acre site is not pleasant, no matter what the conditions,” he tweeted.

In 2015, Blankenship was convicted on a single misdemeanor count of violating federal safety laws at the mine in Montcoal, West Virginia. The disaster occurred when a spark from a longwall machine ignited a pocket of methane gas, which, in turn, set off a massive coal dust explosion throughout the mine.

Multiple and grave safety violations occurred at the mine when Blankenship issued an order to “run coal,” flouting regulations designed to prevent explosions. In an October 2005 memo to the company’s deep mine superintendents, Blankenship outlined his priorities. “If any of you have been asked by your group presidents, your supervisors, engineers or anyone else to do anything other than run coal (i.e., build overcasts, do construction jobs, or whatever), you need to ignore them and run coal,” he wrote.

He demanded reports every 30 minutes on how many tons of coal were being mined. He was to be told at once if the longwall miner was stopped for any reason.

Four investigations of the disaster found that bits on the longwall machine were broken and worn out, causing sparking. Water nozzles meant to keep the bits cool and prevent sparks were also broken. Proper ventilation to prevent the buildup of methane gas was lacking. Explosive coal dust was allowed to accumulate throughout the mine.

Had standard safety procedures designed to prevent these conditions been followed, the 29 miners would not have died.

Federal prosecutors and the Obama administration hailed the conviction of Blankenship as the first conviction of a coal executive in connection with a mining disaster.

The trial and conviction of Blankenship on minor charges was a component of a broader cover-up of the entire coal industry and the state and federal officials who are responsible for ensuring safety in the mines. The coal boss himself walked away from the Upper Big Branch explosion with two years’ pay and a $12 million pension.

Prosecutors made sure that the trial excluded evidence about the explosion and the death of the miners, limiting the charges to violations of mine safety regulations and securities and exchange laws. Blankenship was acquitted on the latter charges, which carried much longer sentences than the charges related to mine safety.

No charges were brought against officials of the Mine Safety and Health Administration, MSHA, the federal agency responsible for inspecting mines and ensuring that they are run safely. MSHA allowed the Upper Big Branch mine to operate even though inspectors had issued over 600 safety violation notices over the previous 18 months, including hundreds for allowing the buildup of coal dust and problems with the ventilation system.

Despite this record of safety violations, MSHA officials took no action to close the mine or even increase the frequency of inspections. Instead, token fines were imposed against the company, most of which were reduced or dropped on appeal.

The United Mine Workers of America (UMWA) also bears responsibility for the deaths of the 29 men. Massey was able to operate the way it did because of a massive union-busting drive carried out with the complicity of the UMWA leadership in 1984-85. At that time, A. T. Massey organized the breaking of the union in the course of a strike in which state police were used to protect scabs and terrorize miners and their families. The defeat of the union was made possible by the isolation of the strike imposed by the UMWA leadership of Richard Trumka and Cecil Roberts.

The union defeat at A.T. Massey was followed by a similar defeat at Pittston, where once again the UMWA leadership worked to isolate and undermine the strike.

Today, the UMWA is a shell of what it once was. There are fewer than 10,000 working miners who belong to the union. There are no UMWA mines in all of Kentucky.

Trumka was rewarded for his treachery by being made president of the AFL-CIO, while Roberts was elevated to the presidency of the UMWA.

Nor has there been any improvement in safety in the seven years since the Upper Big Branch disaster. This is most clearly shown by the resurgence of black lung among coal miners. On average, 500 miners a year are dying from the painful disease, which is hitting miners at younger ages than ever before.

The cause of the rise of black lung is the coal operators’ push for production and profits with the introduction of mining techniques that produce higher levels of coal and rock dust.