In 2014, the Environmental Protection Agency charged 187 defendants with environmental crimes and sentenced offenders to a combined 155 years of jail time. That’s more than double the amount of jail time eco-offenders were sentenced to in 2010, according agency data.

The EPA, however, charged significantly fewer people for environmental crimes in 2014 compared to 2010, reflecting the agency’s strategy of going after larger, more lucrative criminal and civil cases.

“By taking on large, high impact enforcement cases, EPA is helping to level the playing field for companies that play by the rules, while maximizing our ability to protect the communities we serve across the country,” Cynthia Giles, head of the EPA’s Office of Enforcement and Compliance Assurance, said in a statement.

EPA data shows the agency raked forced companies and other offenders to pay $9.7 billion in actions and to pay for “equipment to control pollution and clean up contaminated sites” as well as $163 million in civil penalties and criminal fines. The agency also got offenders to pay $453.7 million to clean up Superfund sites.

EPA enforcement actions resulted in 141 million pound reduction in of air pollutants and a 337 million pound reduction in water pollutants, according to agency data. Enforcement actions also cleaned up 856 million cubic yards of contaminated aquifers.

“Despite challenges posed by budget cuts and a government shutdown, we secured major settlements in key industry sectors and brought criminal violators to justice,” Giles said. “This work resulted in critical investments in advanced technologies and innovative approaches to reduce pollution and improve compliance.”

But probably EPA’s most startling statistic is its more than doubling of prison sentencing for environmental criminals in the last four years. In 2010, the EPA successfully charged 289 defendants, garnering 72 years in prison sentences.

Jail time for offenders has now doubled to 155 years among a successfully convicted group of only 187 defendants.

So who were some of the top environmental criminals of 2014?

Mark Kamholz, the environment control manager at the Tonawanda Coke Corporation, was convicted of violating the Clean Air Act and other federal laws and sentenced to one year in prison, 100 hours of community service and a $20,000 fine.

All this for “releasing coke oven gas containing benzene into the air through an unreported pressure relief valve” and because a coke-quenching tower did not have federally mandated pollution control technology, says EPA. Kamholz order another employee to conceal the fact a pressure valve was releasing pollutants into the air.

The Tonawanda Coke Corporation was hit with fines as well. The company was forced to pay a $12.5 million penalty and pay $12.2 million in community service payments for violating federal environmental laws. The EPA says this is “one of the largest fines ever levied in an air pollution case involving a federal criminal trial.”

Ohio waste disposal company owner Benedict Lupo was sentenced to two years in prison and a $25,000 fine for ordering his employees to dump waste from hydraulic fracturing operations into a tributary of the Mahoning River. Lupo illegally dumped fracking waste into the tributary 30 times in 2012 and 2013, having his employees dump the waste at night when nobody else was around.

Robert Lewis, a hazardous waste transporter, was sentenced to 10 months in federal prison for illegally storing hazardous waste in a self-storage facility in Macon, Georgia. He also illegally stored waste in Rex, Georgia and at his home in Albany.

And finally, Benjamin Pass, the owner of a recycling business, was sentenced to 42 months in prison and forced to pay $21 million in fines for “mishandling of used oil contaminated with polychlorinated biphenyls (PCB) that led to widespread contamination and millions of dollars in clean-up costs.” Pass also fined $539,000 for not paying incomes between 2002 and 2011.