Results of EPA’s Section 610 Review of the Final Rule for Control of 

Emissions of Air Pollution from Nonroad Diesel Engines and Fuel

EPA Office of Transportation and Air Quality

September, 2014

On June 29, 2004, (69 FR 38958), EPA published emission standards for nonroad 

diesel engines to reduce tailpipe emissions. EPA implemented this rule primarily to 

significantly reduce emissions of diesel particulate matter (PM) emissions and of nitrogen 

oxides (NOx), a contributor to ozone formation. The rulemaking also required refiners to

very significantly reduce the sulfur content of the nonroad diesel fuel they produce, to 

minimize the damaging effects of diesel sulfur content on the new catalytic systems 

manufacturers would be using to meet the stringent emission standards. 

Pursuant to Section 610 of the Regulatory Flexibility Act (RFA), EPA has 

completed a review of this rule to determine whether the provisions that could affect

small entities should be continued without change, or should be rescinded or amended to 

minimize adverse economic impacts on small entities. As discussed below, we have 

concluded that no changes in the rule are warranted.

Background

As EPA began to develop the rule, we formally evaluated the potential impacts of 

the program on small businesses according to the requirements of the Small Business 

Regulatory Enforcement Fairness Act (SBREFA), which is part of the Regulatory

Flexibility Act. During this process, we assessed the potential impact of the rule on the 

types of small companies that would be directly affected by the rule – nonroad diesel 

engine manufacturers, nonroad diesel equipment manufacturers, and the diesel fuel 

production and distribution industry (including diesel fuel refiners, importers, 

distributors, and marketers). EPA determined that several companies in these categories 

met the SBA criteria as small entities, and we took the additional steps specified by 

SBREFA to identify and address concerns of these small entities. A federal interagency

Small Business Advocacy Review (SBAR) Panel convened and considered the available 

information from small entities and other sources. The Panel made several 

recommendations for EPA to consider in the rule, and we proposed and took comment on 

these recommendations. 

In the final rule, EPA adopted most of the recommendations of the Panel,

finalizing special provisions for manufacturers of each horsepower category of nonroad 

engines and transition and hardship provisions for small manufacturers of nonroad 

equipment. In addition, EPA also finalized transition provisions for small diesel fuel 

refiners and importers, and hardship provisions for all diesel fuel refiners and importers. 

Although we did not conclude that special provisions were warranted for small diesel fuel 

distributors and marketers, we did finalize general provisions to relieve the compliance 

burden. 
Discussion of the Five Statutory Factors

As discussed below, EPA has reviewed the 2004 Nonroad Diesel Engines and 

Fuel Rule with respect to the five factors set forth in Section 610 of the RFA.

1. Continued Need for the Rule

One of the factors that must be considered in a Section 610 review is the 

continued need for the rule under review. Emissions from nonroad diesel vehicles and 

their fuel contribute to ambient levels of ozone and PM, pollutants for which EPA has 

established health-based National Ambient Air Quality Standards (NAAQS). These 

pollutants are linked with respiratory and/or cardiovascular problems and other adverse 

health impacts leading to increased medication use, hospital admissions, emergency

department visits, and premature mortality. Over 149 million people currently live in 

areas designated nonattainment for one or more of the current NAAQS.1 Pollutant 

reductions from this rule are very large and continue to protect public health, improve air 

quality, and help states meet national air quality standards. Specifically, we projected 

that by 2030, when the fleet will have largely turned over, the rule will reduce NOx 

annually by over 738,000 tons and PM by 129,000 tons.

The provisions of the rule applying to all nonroad engine manufacturers and 

diesel fuel refiners and their related industries have proven to be feasible and effective.

EPA concludes that the rule continues to be necessary, feasible, and effective.

2. Nature of Complaints or Comments Received Concerning the Rule

EPA did not receive any comments during the public comment period for this 

Section 610 review. 

3. Complexity of the Rule

The Agency must also consider the complexity of the rule under review. 

Although cost-effectively achieving the air pollution improvements of the program 

required us to establish a number of regulatory provisions, we carefully coordinated the 

various requirements and worked with industry participants, large and small, to facilitate 

implementation. The rule also included a number of provisions aimed at easing the 

burden of compliance for all affected nonroad engine and equipment manufacturers and 

nonroad diesel fuel refiners, including small refiners. 

4. Extent to which the rule overlaps, duplicates, or conflicts with other Federal, 

State, or local government rules

The Agency must also consider the extent to which the rule overlaps, duplicates, 

or conflicts with other Federal, State, or local government rules. As with previous diesel 

 

1

Summary Nonattainment Area Population Exposure Report, current as of December 13, 2013 at: 

http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR-2011-0135.
engine and fuel regulations, we specifically designed the requirements and phase-in 

schedule for the nonroad diesel engine and fuel program to build on the existing Federal 

programs and to mesh with and complement diesel engine-related programs in California 

and other states. Similarly, we designed the phase-in for the diesel fuel sulfur 

requirements and the small refiner provisions to transition smoothly and to coexist with 

the earlier Tier 2 gasoline sulfur and highway diesel fuel sulfur requirements, so that 

refiners could integrate the implementation of both programs. We are not aware of any 

overlap, duplication, or conflict with other similar programs administered by EPA or 

other agencies.

5. Relevant Changes to Technology, Economic Conditions, or Other Factors

Finally, the Agency must consider the degree to which technology, economic 

conditions, or other factors have changed in the area affected by the rule under review. 

Refinery diesel sulfur reduction technology has continued to evolve over the past decade. 

In addition, heavy-duty engine manufacturers have continuously improved their engine 

technologies, including emission-related technologies, over the years. EPA does not 

believe that these changes, or the general economic fluctuations that the refining and 

engine/vehicle manufacturing industries have faced, have introduced any significant 

additional burdens on small entities subject to this rule.

Conclusion

Based on EPA’s Section 610 review of the 2004 Nonroad Diesel Engine and 

Diesel Fuel Sulfur final rule, as discussed in this document, EPA is not making any 

amendments to the rule. As part of any future rulemakings related to these industries, 

EPA will continue to work with small-entity representatives to minimize any potential

unfavorable impacts on these companies while meeting the need for emission reductions.