United States: U.S. EPA Expands Mobile Source Enforcement Initiative Targeting Operators Of Heavy-Duty Trucking Fleets

While much has been made of U.S. EPA's alleged scaling back of enforcement on various fronts and other policy changes, a wave of enforcement against mobile source engines appears ready to break on the heavy-duty diesel industry. U.S. EPA-Region 3 has initiated criminal prosecution for such a case, and this may be the beginning of a new wave of enforcement by the regions, similar to prior enforcement initiatives such as New Source Review and specific hazardous air pollutant cases against industry sectors.

U.S. EPA recently delegated the authority to prosecute mobile source violations from headquarters to the regions. This delegation is resulting in an increased number of enforcement actions against smaller entities not typically subject to U.S. EPA scrutiny, such as fleets of heavy-duty engine operators and small/mid-sized diesel mechanic shops.

Regulation of Heavy-Duty Diesel Engines

Mobile sources are regulated much differently than stationary sources under the Clean Air Act. For example, stationary sources receive permits for air emissions, but mobile sources are not required to obtain air emission permits. Instead, mobile sources are regulated through design and operational technology standards that apply when they are manufactured. Beginning in 2000, U.S. EPA established regulations specifically applicable to heavy-duty diesel engines. Under this program, U.S. EPA has required diesel engine manufacturers to install specific emission controls, such as filters to block particulate matter, and urea injection systems to control nitrogen oxide formation in these engines. These emissions controls have been the source of contention in the industry, as companies have observed that these systems create significant back pressure in exhaust systems, causing the engines to foul more quickly, increasing engine wear and lengthening service time. In addition, operators complain that the electronic control modules are unreliable, rendering vehicles inoperable and jeopardizing long-haul truckers' livelihoods.

Recent Criminal Action

In a recent criminal case filed at the request of U.S. EPA in the Middle District of Pennsylvania (U.S. v. Rexer et al.), the agency brought a criminal action against a group of heavy-duty diesel truck operators, as well as the mechanic who serviced those vehicles and who allegedly disabled emission control systems on those vehicles in violation of Section 205 of the Clean Air Act. Notably, this action appears to be the first criminal case brought by one of U.S. EPA's regions (specifically Region 3) following U.S. EPA Director of Air Enforcement Phil Brooks' announcement in February 2018 that the agency intends to increase mobile source enforcement. Brooks cited anecdotal reports that up to 30% of used long-haul trucks show evidence of tampering with the emission control systems.

Enforcement Initiative Outlook

This enforcement initiative is worth monitoring for a number of reasons. U.S. EPA's renewed focus on mobile source emissions appears to have been prompted by the now infamous Volkswagen case and has caused U.S. EPA to look more closely at the heavy-duty diesel industry. Traditionally, mobile source violations have been difficult to identify. Relevant vehicles are often located in areas where they are subject to an inspection and maintenance program and must be emissions tested, but annual testing is not required. In addition, long-haul trucks have historically been regulated more closely by the U.S. Department of Transportation ("DOT") than U.S. EPA. Now the two agencies appear to be collaborating on these issues, which apparently led to the sharing of information underlying the Rexner criminal action. In that case, the Pennsylvania DOT determined that the emission control systems on the relevant trucks were inoperative and notified U.S. EPA.

Whether other state agencies will follow Pennsylvania's lead remains to be seen, but companies that lease or operate heavy-duty diesel transportation fleets should take note. Members of the industry frequently take issue with the U.S. EPA emission control requirements, arguing that the requirements put them at a competitive disadvantage and wear out the engines prematurely. Industry's well known concerns with the stringent requirements may be fueling U.S. EPA's assumption that a large number of used vehicles have been subject to tampering. In the past, it was difficult for U.S. EPA to detect these violations other than in rare cases where the agency directly sought information from diesel mechanics by requesting copies of their maintenance records to investigate whether the shop had been disabling emission controls. Now that the U.S. DOT, state DOTs and the U.S. EPA are collaborating more closely on these issues, U.S. EPA can let these other agencies do the investigative work that U.S. EPA traditionally has not done. Instead, U.S. EPA can monitor reports of vehicles U.S. DOT or state DOTs removed from the road because the emission control systems were disabled and pursue these matters through enforcement.

Recommendations for the Industry

Given the increase in enforcement in this area, owners and operators of transportation vehicles should consider adopting a formal written policy expressly prohibiting employees from disabling or altering any part of the emission control system on the company's vehicles and implementing a compliance verification program to confirm that the emission control systems remain in operation, perhaps as part of the regularly scheduled engine maintenance program. These measures will serve key corporate compliance objectives, including (i) the prompt identification and remediation of potentially noncompliant vehicles before the government discovers the issue, (ii) providing documentation of good faith efforts to comply and refuting allegations that the company disregarded emission control requirements and profited from such noncompliance, and (iii) demonstrating a corporate commitment to sustainable and compliant operations.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

Similar Articles
Relevancy Powered by MondaqAI
In association with
Related Topics
Similar Articles
Relevancy Powered by MondaqAI
Related Articles
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Mondaq Sign Up
Gain free access to lawyers expertise from more than 250 countries.
Email Address
Company Name
Confirm Password
Mondaq Newsalert
Select Topics
Select Regions
Registration (you must scroll down to set your data preferences)

Mondaq Ltd requires you to register and provide information that personally identifies you, including your content preferences, for three primary purposes (full details of Mondaq’s use of your personal data can be found in our Privacy and Cookies Notice):

  • To allow you to personalize the Mondaq websites you are visiting to show content ("Content") relevant to your interests.
  • To enable features such as password reminder, news alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our content providers ("Contributors") who contribute Content for free for your use.

Mondaq hopes that our registered users will support us in maintaining our free to view business model by consenting to our use of your personal data as described below.

Mondaq has a "free to view" business model. Our services are paid for by Contributors in exchange for Mondaq providing them with access to information about who accesses their content. Once personal data is transferred to our Contributors they become a data controller of this personal data. They use it to measure the response that their articles are receiving, as a form of market research. They may also use it to provide Mondaq users with information about their products and services.

Details of each Contributor to which your personal data will be transferred is clearly stated within the Content that you access. For full details of how this Contributor will use your personal data, you should review the Contributor’s own Privacy Notice.

Please indicate your preference below:

Yes, I am happy to support Mondaq in maintaining its free to view business model by agreeing to allow Mondaq to share my personal data with Contributors whose Content I access
No, I do not want Mondaq to share my personal data with Contributors

Also please let us know whether you are happy to receive communications promoting products and services offered by Mondaq:

Yes, I am happy to received promotional communications from Mondaq
No, please do not send me promotional communications from Mondaq
Terms & Conditions

Mondaq.com (the Website) is owned and managed by Mondaq Ltd (Mondaq). Mondaq grants you a non-exclusive, revocable licence to access the Website and associated services, such as the Mondaq News Alerts (Services), subject to and in consideration of your compliance with the following terms and conditions of use (Terms). Your use of the Website and/or Services constitutes your agreement to the Terms. Mondaq may terminate your use of the Website and Services if you are in breach of these Terms or if Mondaq decides to terminate the licence granted hereunder for any reason whatsoever.

Use of www.mondaq.com

To Use Mondaq.com you must be: eighteen (18) years old or over; legally capable of entering into binding contracts; and not in any way prohibited by the applicable law to enter into these Terms in the jurisdiction which you are currently located.

You may use the Website as an unregistered user, however, you are required to register as a user if you wish to read the full text of the Content or to receive the Services.

You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these Terms or with the prior written consent of Mondaq. You may not use electronic or other means to extract details or information from the Content. Nor shall you extract information about users or Contributors in order to offer them any services or products.

In your use of the Website and/or Services you shall: comply with all applicable laws, regulations, directives and legislations which apply to your Use of the Website and/or Services in whatever country you are physically located including without limitation any and all consumer law, export control laws and regulations; provide to us true, correct and accurate information and promptly inform us in the event that any information that you have provided to us changes or becomes inaccurate; notify Mondaq immediately of any circumstances where you have reason to believe that any Intellectual Property Rights or any other rights of any third party may have been infringed; co-operate with reasonable security or other checks or requests for information made by Mondaq from time to time; and at all times be fully liable for the breach of any of these Terms by a third party using your login details to access the Website and/or Services

however, you shall not: do anything likely to impair, interfere with or damage or cause harm or distress to any persons, or the network; do anything that will infringe any Intellectual Property Rights or other rights of Mondaq or any third party; or use the Website, Services and/or Content otherwise than in accordance with these Terms; use any trade marks or service marks of Mondaq or the Contributors, or do anything which may be seen to take unfair advantage of the reputation and goodwill of Mondaq or the Contributors, or the Website, Services and/or Content.

Mondaq reserves the right, in its sole discretion, to take any action that it deems necessary and appropriate in the event it considers that there is a breach or threatened breach of the Terms.

Mondaq’s Rights and Obligations

Unless otherwise expressly set out to the contrary, nothing in these Terms shall serve to transfer from Mondaq to you, any Intellectual Property Rights owned by and/or licensed to Mondaq and all rights, title and interest in and to such Intellectual Property Rights will remain exclusively with Mondaq and/or its licensors.

Mondaq shall use its reasonable endeavours to make the Website and Services available to you at all times, but we cannot guarantee an uninterrupted and fault free service.

Mondaq reserves the right to make changes to the services and/or the Website or part thereof, from time to time, and we may add, remove, modify and/or vary any elements of features and functionalities of the Website or the services.

Mondaq also reserves the right from time to time to monitor your Use of the Website and/or services.


The Content is general information only. It is not intended to constitute legal advice or seek to be the complete and comprehensive statement of the law, nor is it intended to address your specific requirements or provide advice on which reliance should be placed. Mondaq and/or its Contributors and other suppliers make no representations about the suitability of the information contained in the Content for any purpose. All Content provided "as is" without warranty of any kind. Mondaq and/or its Contributors and other suppliers hereby exclude and disclaim all representations, warranties or guarantees with regard to the Content, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. To the maximum extent permitted by law, Mondaq expressly excludes all representations, warranties, obligations, and liabilities arising out of or in connection with all Content. In no event shall Mondaq and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use of the Content or performance of Mondaq’s Services.


Mondaq may alter or amend these Terms by amending them on the Website. By continuing to Use the Services and/or the Website after such amendment, you will be deemed to have accepted any amendment to these Terms.

These Terms shall be governed by and construed in accordance with the laws of England and Wales and you irrevocably submit to the exclusive jurisdiction of the courts of England and Wales to settle any dispute which may arise out of or in connection with these Terms. If you live outside the United Kingdom, English law shall apply only to the extent that English law shall not deprive you of any legal protection accorded in accordance with the law of the place where you are habitually resident ("Local Law"). In the event English law deprives you of any legal protection which is accorded to you under Local Law, then these terms shall be governed by Local Law and any dispute or claim arising out of or in connection with these Terms shall be subject to the non-exclusive jurisdiction of the courts where you are habitually resident.

You may print and keep a copy of these Terms, which form the entire agreement between you and Mondaq and supersede any other communications or advertising in respect of the Service and/or the Website.

No delay in exercising or non-exercise by you and/or Mondaq of any of its rights under or in connection with these Terms shall operate as a waiver or release of each of your or Mondaq’s right. Rather, any such waiver or release must be specifically granted in writing signed by the party granting it.

If any part of these Terms is held unenforceable, that part shall be enforced to the maximum extent permissible so as to give effect to the intent of the parties, and the Terms shall continue in full force and effect.

Mondaq shall not incur any liability to you on account of any loss or damage resulting from any delay or failure to perform all or any part of these Terms if such delay or failure is caused, in whole or in part, by events, occurrences, or causes beyond the control of Mondaq. Such events, occurrences or causes will include, without limitation, acts of God, strikes, lockouts, server and network failure, riots, acts of war, earthquakes, fire and explosions.

By clicking Register you state you have read and agree to our Terms and Conditions