California officials say the Trump administration’s plan to roll back car-mileage standards is not supported by science, will damage people’s health and exacerbate climate change.

California Attorney General Xavier Becerra and California Air Resources Board chairwoman Mary Nichols were among several state officials on the first panel to testify at a hearing in Fresno on Monday. The hearing is intended to seek public comment on the administration’s mileage plan.

The proposal would freeze U.S. mileage standards at levels mandated by the Obama administration for 2020 instead of letting them rise to 36 miles per gallon (15 kilometers per liter) by 2025.

Nichols said the administration’s claims that the rollback would improve safety were absurd. Becerra said California could not afford to retreat in the fight against climate change.