U.S. President Joe Biden has vetoed Republican-led efforts to strike down plans to dramatically tighten the emissions standards for heavy-duty engines and vehicles.

In late May, Congress voted to nullify Environmental Protection Agency (EPA) emissions rules that would apply beginning in Model Year 2027, placing a particular focus on nitrogen oxides (NOx).

Under the rules, NOx emissions will be 80% tighter than those that apply today, while mandated warranties on emissions controls will be 2.8 to 4.5 times longer. Manufacturers will also have to demonstrate that their designs would prevent tampering by drivers.

The underlying standards will also target emissions over a broader range of operating conditions, like the low-load situations that reduce the effectiveness of selective catalytic reduction-based systems. Such conditions account for more than half the NOx emissions during a vehicle’s typical workday.

“The rule cuts pollution, boosts public health, and advances environmental justice in communities across the country. It will prevent hundreds, if not thousands, of premature deaths; thousands of childhood asthma cases; and millions of missed school days every year,” Biden said in a statement about the veto.

“The resolution would deny communities these health benefits by resulting in weaker emissions standards for heavy-duty vehicles and engines, which are significant sources of pollutants that threaten public health. If enacted, the resolution would squander $36 billion in benefits to society — and an opportunity to lead on the defining crisis of our time.”

Overriding a veto

Overriding a veto would require a 2/3 majority vote in the House and Senate, but the now-vetoed efforts to defeat the rules only passed through the Senate in a 50-49 vote.

“President Biden chose to prioritize his extreme environmental agenda over bipartisan pushback from Congress,” tweeted Nebraska Senator Deb Fischer, one of the key voices opposing the regulations.

“This veto is more than just a slap in the face to truckers, who transport nearly every consumer good. Pushing this excessive regulation forward will also raise prices for families already grappling with inflation.”

EPA estimates that, by 2045, the stronger rules will help to realize up to 2,900 fewer premature deaths, 6,700 fewer hospital admissions and emergency department visits, and 78,000 fewer lost workdays, among other benefits.

Related hardware updates to Model Year 2027 trucks and engines are projected to cost an extra $25,000 to $30,000.

“While we are disappointed in the president’s decision to veto this bipartisan legislation, we thank the Democrats and Republicans in Congress who put politics aside in support of small business truckers simply trying to navigate wave after wave of EPA regulations,” Owner-Operator Independent Drivers Association (OOIDA) president Todd Spencer said in a statement.

“As the White House issues their veto, EPA is working to finalize another round of burdensome emissions requirements and pushing for electric commercial trucks without any practical concern regarding purchasing costs, mileage range, battery weight, or charging availability.”

The latest round of proposed limits on greenhouse gas (GHG) emissions would apply to Model Year 2028-32 medium- and heavy-duty engines and vehicles, and reopen rules that were previously established for Model Year 2027.

Canadian regulators have traditionally mirrored emissions standards enacted by the U.S. EPA.