Bill to force EPA to retool DEF rules to prevent diesel engine shutdowns in extreme cold

Lawmakers are eyeing a plan to force changes to Environmental Protection Agency (EPA) emissions system rules in order to curb diesel engine shutdowns caused by very cold weather.

The Cold Weather Diesel Reliability Act was recently introduced by U.S. Senators Dan Sullivan (R-Alaska) and Cynthia Lummis (R-Wyo.).

The bill would require revisions to the EPA’s Clean Air Act so that diesel engine manufacturers would be authorized to suspend inducement-related engine derate or shutdown functions that are triggered by emissions control system faults when ambient temperatures are at or below zero degrees Centigrade.

The manufacturer would ensure that the engine returns to normal emission control operation, including inducement enforcement, once ambient temperatures rise above zero degrees. 

Also under the Cold Weather Diesel Reliability Act, the EPA would be required to grant a year-round exemption from diesel exhaust fluid (DEF) system requirements for vehicles primarily operated north of 59 degrees north latitude, or vehicles that encounters operational or logistical conditions characterized by prolonged ambient temperatures that are below the freezing point of DEF or that otherwise make the use of the DEF system impractical.

“Under current one-size-fits-all EPA regulations, trucks and heavy equipment are required to use emissions systems that can trigger engine shutdowns when DEF —which freezes at just 12 degrees Fahrenheit—fails to reach proper operating temperatures, even though the engine itself is working normally. This legislation directs the EPA to update its regulations to account for how diesel engines actually operate in cold-weather states, like Alaska and Wyoming, to prevent the automatic shutdowns caused by cold-related emissions faults, and to provide year-round exemptions from DEF system requirements for vehicles and equipment that operate primarily in cold weather climates,” Sullivan said in a news release announcing the bill.

“Climate-alarmist bureaucrats in Washington do not understand that the consequences of their radical agenda are hurting real people in western communities,” said Lummis. “I am proud to join Senator Sullivan in correcting the Obama and Biden administrations’ disastrous policies and ensuring folks don’t get stranded in their ‘EPA-compliant’ vehicles, even during the harshest winter weather. The people of Wyoming should not have to choose between breaking the law or losing their lives.”