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Press Release

San Marcos Companies and Executives Charged with Tampering with Emission Control Devices on Diesel Truck Fleet

For Immediate Release
U.S. Attorney's Office, Southern District of California

Assistant U.S. Attorney Melanie K. Pierson (619) 546-7976


SAN DIEGO – A federal grand jury in San Diego today returned a six-count indictment charging three San Marcos companies, two managers and a technician with various felonies related to tampering with emission control devices on heavy-duty diesel trucks.

Diamond Environmental Services LP, Diamond Maintenance Services, LLC and Diamond Solid Waste, Inc. (collectively “Diamond”) of San Marcos, California, plus owner and manager Arie Eric De Jong III,  manager Warren Van Dam and technician Jorge Leyva Rodriguez of ECM Diesel Programming were charged with conspiring to manipulate the electronic control module (ECM) on Diamond’s fleet of heavy duty diesel trucks.  The alleged manipulation was designed to disable the monitoring system that would otherwise cause the truck to effectively become non-operational if the diesel emissions filter became too dirty with diesel particulates. 

Since model year 2008, EPA regulations required all heavy-duty diesel trucks to be equipped with a computerized system of electronics and sensors that monitored all emission-related engine systems and components.  If a malfunction or problem occurred within the emission system - for example, the diesel particulate filter, or DPF, became dirty with soot that needed to be “regenerated” or burned off - the monitoring system would cause a Malfunction Indicator/Check Engine Light to be illuminated in the truck’s cabin.  If the hardware emission system problem was not resolved, the monitoring system could limit the top speed of the truck to as low as five miles per hour (an effect commonly referred to as “limp mode” or “power reduced mode”), providing an incentive for the truck’s operator to repair the truck.

The indictment alleges that the defendants agreed to reprogram the ECMs to avoid the costs associated with the need to regenerate the diesel particulate filters (DPFs) on the heavy-duty diesel trucks in the fleets operated by defendant Diamond Environmental Services, LP and Diamond Solid Waste Services, Inc., and maintained by Diamond Maintenance Services, LLC.  According to the indictment, employees removed the ECMs from trucks in their fleet and shipped them out of California to be reprogrammed, and, in addition, defendant Jorge Martin Leyva Rodriguez travelled from Mexico to Diamond locations in San Marcos and San Diego to reprogram the ECMs. 

The indictment alleges that, in order to keep trucks operating with DPFs that had not been cleaned by regeneration, employees punched holes through the honeycomb cores of the DPFs on some of the heavy-duty diesel trucks to allow the free flow of air through this portion of the emission system, without filtration. It is further alleged that in order to conceal the fact that the emissions systems on some of the heavy-duty diesel trucks were not operating properly, employees prepared false opacity (smog) test results for such trucks, using an entirely different truck to achieve passing results.  According to the indictment, when the co-conspirators learned that action by the authorities was imminent, defendant Rodriguez returned to the Diamond facilities to reprogram the software of the ECMs on the truck fleet in order to conceal the 2016 alterations.  Defendants Diamond Environmental Services, LP, Arie Eric De Jong III and Jorge Levya Rodriguez are charged with evidence tampering, based on the later alterations to the ECMs.

“We are all the victims of environmental crime,” said U.S. Attorney Robert Brewer. “We aren’t going to allow companies to take shortcuts and pollute the environment.” Brewer praised prosecutor Melanie Pierson and investigators from the FBI and the U.S. Environmental Protection Agency, Criminal Investigation Division, for protecting the public.

San Diego FBI Acting Special Agent in Charge Suzanne Turner noted, “Today’s indictments underscore the FBI’s continued commitment to our law enforcement partners in combatting environmental crime in San Diego County. The alleged activity impacts every citizen and visitor to San Diego by contributing to declining air quality and increasing public exposure to airborne pollutants. The FBI will continue to work diligently to protect the citizens of San Diego County from entities engaged in illegal business practices which result in environmental harm.”

“The defendants have been charged with conspiring to violate the Clean Air Act and tampering with the emissions control equipment on their commercial diesel trucks,” said Special Agent-in-Charge Jay M. Green of EPA’s criminal enforcement program in California. “The alleged crimes would increase air pollution linked to respiratory illnesses and environmental degradation. Today’s indictment serves as a reminder that EPA and our partners are steadfast in our commitment to protect human health and the environment.”

DEFENDANTS                                             Criminal Case No. 18cr5382-GPC

Diamond Environmental Services, LP           Organized: 1997                     San Marcos, California

Diamond Maintenance Services, LLC           Organized: 2004                     San Marcos, California

Diamond Solid Waste Services, Inc.              Incorporated: 2010                  San Marcos, California

Arie Eric De Jong III                                      Age: 52                                   San Marcos, California

Warren L. Van Dam                                       Age: 52                                   San Marcos, California

Jorge Leyva-Rodriguez                                  Age: 51                                   El Centro, California


Count 1

Conspiracy to Tamper with Monitoring Devices, 18 U.S.C. § 371

Maximum penalty: Five years in prison, fine of $250,000 ($500,000 for an organization)

Count 2-4 (charging Diamond Environmental Services, LP and De Jong)

Tampering with Monitoring Device, 42 U.S.C. §7413

Maximum Penalty:  Two years in custody and/or $250,000 fine ($500,000 fine for an organization)

Count 5 (charging Diamond Environmental Services, LP; De Jong, Van Dam and Leyva-Rodriguez)

Tampering with Monitoring Device, 42 U.S.C. §7413

Maximum Penalty:  Two years in custody and/or $250,000 fine ($500,000 fine for an organization)

Count 6 (charging Diamond Environmental Services, LP; De Jong and Leyva-Rodriguez)

Evidence Tampering, 18 U.S.C. §1512(c)(1)

Maximum Penalty: Twenty years and/or $250,000 fine


Federal Bureau of Investigation

U.S. Environmental Protection Agency, Criminal Investigation Division

*The charges and allegations contained in an indictment or complaint are merely accusations, and the defendants are considered innocent unless and until proven guilty.

Updated April 11, 2019

Press Release Number: CAS19-0411-Diamond