Regulatory

Announcement

Office of Transportation

and Air Quality

EPA420-F-05-028

October 2005

EPA Proposes Effective Date 

for Diesel Fuel Sulfur Control 

Requirements in Rural Alaska

The U.S. Environmental Protection Agency (EPA) is proposing to 

modify the diesel fuel regulations to apply an effective date of June 1, 

2010, for the sulfur, cetane and aromatics requirements for highway, 

nonroad, locomotive and marine diesel fuel produced or imported for, 

distributed to, or used in the rural areas of Alaska. On that date, rural 

Alaska would catch up with the implementation schedule of the rules 

that are applicable in the rest of the United States, providing the full 

environmental benefits of these programs to rural Alaska. On June 1, 

2010, all diesel fuels would have to meet a 15 parts per million (ppm) 

(maximum) sulfur content standard. This rulemaking would allow 

implementation of the nationwide programs for highway and nonroad 

diesel fuels in Alaska to be consistent with an alternative transition 

program requested by the State.

Background

The pollution emitted by diesel engines contributes greatly to our nation’s continuing air quality problems. Even with more stringent heavyduty highway engine standards that became effective in 2004, diesel 

engines will continue to emit large amounts of nitrogen oxides (NOx) 

and particulate matter (PM), both of which contribute to serious public 

health problems in the United States. Exposure is widespread, particularly in urban areas.
In 2001,we established a comprehensive national control program that 

will regulate heavy-duty highway vehicles and their fuel as a single system. New emission standards will begin to take effect with model year 

2007 and will apply to heavy-duty highway engines and vehicles. 

These standards are based on the use of high-efficiency catalytic exhaust 

emission control devices or comparably effective advanced technologies. 

Because these devices are damaged by sulfur, we also reduced the allowable level of sulfur in highway diesel fuel by 97 percent. This reduction 

to 15 ppm sulfur is required for at least 80 percent of the highway diesel 

fuel beginning June 1, 2006, and the remaining diesel fuel meeting the 

500 ppm sulfur standard must be segregated from the 15 ppm sulfur fuel 

and used only in 2006 and earlier model year highway diesel vehicles. 

Beginning June 1, 2010, all highway diesel fuel must meet the 15 ppm 

sulfur standard.

Similarly, in 2004 we established a comprehensive national program to 

reduce emissions from nonroad diesel engines, locomotives, and marine vessels. Engine manufacturers will produce engines with advanced 

emission-control technologies similar to those upcoming for highway 

trucks and buses. Closely linked to these engine provisions are new fuel 

requirements that will decrease the allowable levels of sulfur in fuel used 

in nonroad diesel engines, locomotives, and marine vessels by more than 

99 percent. 

A reduction from uncontrolled sulfur levels to 500 ppm sulfur begins 

June 1, 2007, and the final reduction to 15 ppm sulfur begins June 1, 

2010, for nonroad diesel fuel, and June 1, 2012, for locomotive and marine vessel diesel fuel. However, nonroad, locomotive, or marine diesel 

fuel with uncontrolled sulfur content (and uncontrolled aromatics content and cetane index) is allowed for EPA-approved small refiners and 

importers. Diesel fuel that is used for other types of application, such as 

heating oil, must be segregated and identified with a yellow marker and 

red dye. 

Alaska under the 2001 Highway Diesel Rule

Since the beginning of the 500 ppm highway diesel fuel program in 

1993, we have granted Alaska exemptions from both the sulfur standard 

and dye provisions because of its unique geographical, meteorological, 

air quality, and economic factors.

Clean 

Diesel 

Truck 

and Bus 

Program

Clean Air 

Nonroad 

Diesel Rule 
Under the 2001 highway diesel rule, the sulfur exemption for Alaska 

terminated and required the State to meet the new low sulfur standards 

taking effect in June 2006 (80% of diesel fuel meeting the 15 ppm requirement). However, based on factors unique to Alaska, we provided 

the State with: (1) an extension of the temporary exemption from the 

500 ppm sulfur standard in the urban areas until the effective date of 

the new 15 ppm sulfur standard; (2) an opportunity to request an alternative implementation plan for the 15 ppm sulfur diesel fuel program; 

and (3) a permanent exemption from the diesel fuel dye provisions.

Alaska under the 2004 Nonroad Diesel Rule

Under the Agency’s Nonroad Rule, engines in Alaska must meet all 

emission requirements. In regards to the fuel sulfur requirements, full 

implementation was applied to urban Alaska (rural Alaska would be 

addressed in a separate rulemaking). In addition, rural areas of Alaska 

were exempt from the segregation and dye provisions for its heating oil. This was due to the fact that 95% of the distillate fuel (diesel 

+ heating oil) is used for heating oil, and only 5% for highway and 

nonroad applications due to the largely subsistence economy of remote 

rural areas of Alaska. While the State cannot obtain early use credits, 

small refiners may apply for flexibilities if it obtains approval from the 

EPA for a compliance plan.

To allow coordination between the highway and nonroad diesel sulfur 

requirements in rural Alaska, the 2004 nonroad final rule deferred final 

action on the fuel sulfur standards and implementation deadlines. We 

indicated it would issue a supplemental proposal (i.e., this proposed 

rule) to address the comments submitted by the State for nonroad diesel fuel in the rural areas, as well as the State’s alternative implementation plan for highway diesel fuel in the rural areas. We did, however, 

finalize requirements prohibiting the use of high sulfur diesel fuel 

(greater than 15ppm) in model year 2011 and later nonroad engines.

Rural Alaska is Unique

Alaska requested that the nationwide diesel fuel requirements be applicable to the rural areas, but not until June 1, 2010, to allow those areas 

more time to develop cost effective methods to distribute and store the 

low sulfur diesel fuel. Rural Alaska represents a rather unique situation. The State estimates that highway vehicles consume only about 

one percent of the distillate fuel in the rural areas, while marine en-
gines consume about four percent. “Heating oil” consumes the remaining 

95 percent. There is no significant consumption of nonroad or locomotive diesel fuel in rural Alaska. Thus, there is only a small proportion of 

the distillate fuel that we are regulating for sulfur content (and aromatics 

content and/or cetane index).

Our goal is to allow Alaska to transition to the low sulfur fuel programs 

in a manner that minimizes costs while still ensuring that the small 

number of new vehicles and engines with high-efficiency catalytic 

exhaust emission control devices, or comparably effective advanced 

technologies, receive the 15 ppm sulfur diesel fuel they need. The State 

did not ask for an alternative transition schedule for the urban areas, and 

indicated those areas should be subject to the national implementation 

schedules of the diesel fuel programs.

Public Participation Opportunities

We welcome your comments on this proposed rule. For instructions on 

submitting written comments, please see the Federal Register notice, 

which is available from the EPA Air Docket by calling 202-566-1742; 

please refer to Docket No. OAR-2004-0229. In addition, you can access 

the proposed rule and related documents on EPA’s Office of Transportation and Air Quality (OTAQ) Web site at:

www.epa.gov/otaq/regs/fuels/diesel/diesel.htm

A public hearing is not anticipated, but will be scheduled if requested by 

the public. If a pubic hearing is requested within 30 days of publication 

of this proposal, notice of the hearing will subsequently be published in 

the Federal Register.

For More Information

For more information, please contact David Korotney at:

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

2000 Traverwood Drive

Ann Arbor, MI 48105

(734) 214-4507

E-mail: korotney.david@epa.gov