Cummins Sees EPA Final NOx Rule in December, Days Before Deadline

Cummins expects the EPA to publish its final rulemaking on heavy-duty truck nitrogen oxide emissions in December — just days before the regulation takes effect Jan. 1. The engine maker's CEO, Jennifer Rumsey, flagged the timing on the company's third-quarter 2026 earnings call Nov. 5.

The delay has already cost the market real volume. Rumsey acknowledged that uncertainty over the regulation's fine print dampened Class 8 and medium-duty truck sales and orders over the past two months, and Cummins cut its 2026 North American medium-duty forecast to 125,000–130,000 units, down from the 130,000–140,000 guidance it gave at Q2 earnings.

Heavy-duty held up better. Cummins kept its 2026 North American heavy-duty demand forecast at 240,000–250,000 units after a stronger quarter for the largest trucks, helped by a rebound in the freight market.

What does the final rule actually change?

The draft notice of proposed rulemaking keeps the Biden-era requirement that heavy-duty NOx emissions fall to 35 milligrams per horsepower-hour, down from 200 mg/hp-hr. But it gave manufacturers wiggle room on implementation timing, noncompliance penalties (NCPs) and NOx credits.

EPA has been running behind since Administrator Lee Zeldin announced in March 2025 that the 2022 Heavy-Duty Nitrogen Oxides rule would be re-evaluated, citing consumer choice and cost concerns. Daimler Trucks North America has separately urged the agency to clarify the 2027 standards.

The sticking point for carriers is price. Final details on the sliding scale for noncompliance have not been released. "We anticipate that NCPs will be included in the final rule. The question and what's driving some underlying market uncertainty is will EPA change the [price] of those NCPs from the draft rule?" Rumsey told analysts.

How is Cummins handling the transition?

Cummins was the first engine maker to commit to a staggered introduction of engines meeting the stiffer standards, after EPA opened that flexibility in July. On July 23, the Columbus, Ind.-based company said it would keep building current versions of the X15, X12 and L9 engines — powerplants many truck makers offer in larger trucks and tractors — after analyzing the NPRM.

Rumsey said Cummins is working closely with truck makers on product availability and plans to sell more of its current products in 2027 as the shift to EPA 2027-compliant engines accelerates. Limited production of the new X10 and updated X15 starts in January.

Capacity is tightening where it matters. The Jamestown, N.Y. plant that builds the X15 is set to run at capacity in the fourth quarter of 2026.

How strong was Q3?

The production numbers were blunt. Industrywide heavy-duty truck production hit 70,000 units in Q3, up 62% year over year. Cummins' heavy-duty engine sales totaled 24,000, up 68%.

Medium-duty moved the same direction. Industrywide production reached 36,000 units, a 77% jump from 2025 levels, while Cummins' engine sales in the segment totaled 33,000, up 88% year over year.

Globally, Cummins sold 33,200 heavy-duty engines in Q3, up 48.2% from 22,400 a year earlier. Medium-duty sales climbed 35.8% to 85,700 engines, from 63,100.

The money followed the volumes. Cummins posted Q3 net income of $1.14 billion, more than double the $536 million reported a year ago. Revenue rose 13% to $9.44 billion from $8.32 billion. The engine segment delivered $3.13 billion in sales, up 19.9% from $2.61 billion — a figure that would have been higher but for weakness in North American pickup trucks.

"Global power generation and North America heavy-duty truck demand remain strong, and we expect fourth-quarter revenues to step up from third-quarter levels and set a new record," Rumsey said in comments accompanying the earnings.

Looking ahead, Rumsey said Cummins expects underlying demand to stay strong into 2027, though uncertainty over where NCPs will be priced is still pushing some customers to wait — meaning the December rulemaking's penalty schedule could tip fleet ordering either way.