The Biden-era limits were designed to reduce emissions of toxic pollutants, including a cancer-causing ingredient used in antifreeze and plastics.

Mommy, a Western Santa Cruz tortoise, recently welcomed four hatchlings at the Philadelphia Zoo, where she has lived since 1932.

Recent Trump administration actions are setting the stage for a measles resurgence, experts fear.

Administration officials reversed a decision made during the Biden presidency that would have given millions of people access to weight-loss drugs paid for Medicare and Medicaid.

After years of NASA and private crews returning to Earth near Florida, the company shifted its landing zone to the West Coast for the private Fram2 mission.

As they cling to leaf tips, newborn warty birch caterpillars produce vibrations that can ward off invaders approaching their millimeter-size domain.

The ancient weapons, found in a cave near Marfa, could be among the oldest near-complete set of wood and stone hunting tools found in North America.

President Trump wants to bring pharmaceutical manufacturing back to the United States. Experts warn that tariffs could result in shortages and higher prices for generic drugs.

Born into rural poverty, he climbed to the top of the art market. But he fell after being convicted of selling fake and stolen items.

Hundreds of hours of recordings suggest that the apes can generate meaning by stringing sounds together in pairs. But some scholars are skeptical.

Trump cutbacks were supposedly aimed at administrators. But scientists in food and drug-testing labs and policy experts who advance generic drug approvals were also dismissed.

Across the country, companies have been installing giant batteries that help them use more wind and solar power. That’s about to get much harder.

New research painted a more accurate picture of the megafauna that spread widely around the Americas before they went extinct.

She used her wealth strategically to expand opportunities for women, underwriting the development of the pill and supporting the suffrage movement.

In addition to reductions at agency personnel, federal regulators are demanding $2.9 billion in contract cancellations, The Times has learned.

The facility, in Colstrip, Mont., used a new E.P.A. system for requesting special waivers from President Trump.

It wasn’t the size of human brains that distinguished people from apes, he theorized, but the way they were organized. He found a creative way to prove it.

The reorganization that began on Tuesday will scale back an agency that has been a public health model around the world.

The move threatens to paralyze the Low Income Home Energy Assistance Program, which helps to offset high utility bills for roughly 6.2 million people nationwide.

A growing body of research suggests that preventing the viral infection can help stave off cognitive decline.

A new survey found that 11 percent of Americans said they could not pay for medication and medical treatments.

Before a discovery in a Panamanian rainforest, “it seemed impossible that lightning could be a good thing for the trees,” a scientist said.

The cuts were part of a Trump administration plan announced last week to dismiss thousands of employees and drastically overhaul the Health and Human Services Department under Secretary Robert F. Kennedy Jr.

Health Secretary Robert F. Kennedy Jr. suggests that laying off thousands of federal workers would tame a massive budget. But nearly all of the agency’s money goes to hospitals, doctors and nursing homes.

Senator Josh Hawley, a Republican, pressed Dr. Oz on transgender care and abortion, and now says he will vote for the physician’s confirmation to become head of Medicare and Medicaid.

Large quakes produce shaking at a variety of frequencies. Some waves can travel hundreds of miles, and are amplified by local geological conditions.

The United States was a key supplier of contraceptives in many developing countries. The Trump administration has ended that support.

Suni Williams and Butch Wilmore spoke in their first news conference since returning to Earth two weeks ago from an unexpectedly long I.S.S. stay that lasted more than nine months.

Under microscopes, scientists found that giant single-cell organisms were able to vacuum up more food when they are stuck together.

Since World War II, U.S. research funding has led to discoveries that fueled economic gains. Now cutbacks are seen as putting that legacy in jeopardy.

A pipeline company’s lawsuit against the environmental group could chill free speech, experts said. First Amendment issues are likely to figure prominently in an appeal.

Five years after the pandemic began, interest in the anti-parasitic drug is rising again as right-wing influencers promote it — and spread misinformation about it.

Nearly 2,000 scientists urged that Congress restore funding to federal agencies decimated by recent cuts.

The museum hopes that after learning about the planet’s prehistoric past, people will do more to preserve Earth’s future.

The Eli Lilly drug caused a major drop in the blood levels of Lp(a), but further research is needed to show that it will prevent heart attacks and strokes.

The rocket, developed by Isar Aerospace, lifted off from Norway’s Andøya Space Center and crashed about 30 seconds later. The test flight was part of efforts to make Europe a center for private satellite launches.

The moon slipped between the Earth and the sun on Saturday, casting a shadow on our planet in parts of the United States, Canada, the Caribbean, Europe, Russia and Africa.

Your average daily heart rate is a useful metric; so is your daily step count. Combining the two might be even better.

Dr. Peter Marks, a veteran of the agency, wrote that undermining confidence in vaccines is irresponsible and a danger to public health.

Ranchers in Texas claim livestock was sickened by ‘forever chemicals’ in fertilizer made from sewage sludge. Now Synagro, a Goldman Sachs-backed firm, has lost a deal to manufacture there.

If you’re on the East Coast, wake up early to try and catch the moon take a bite out of the sun on Saturday.

The arrival of spring brings a question: How to manage the disruption brought by climate change?

As the Trump administration threatens to strip accrediting bodies of their power, many are scrambling to purge diversity requirements.

David Geier has been hired as a senior data analyst at H.H.S. According to several people, he will examine any potential links between vaccines and autism that were debunked long ago.

The showdown catapults the interstate abortion wars to a new level.

The best-selling author “got a little emotional” while talking with The Times about the world’s deadliest infectious disease. Listen to the conversation.

Invoking an obscure provision, it said power plants and others could write to ask for exemptions to mercury, arsenic and other restrictions and that “the president will make a decision.”

Researchers in New Zealand have recorded what they believe is the first instance of a shark actively making noise.

After more than a decade of mapping the stars, the European spacecraft will shut down on Thursday. But its legacy lives on.

State health officials worry that declining vaccination rates have left many communities vulnerable nationwide.

Federal officials cited the end of the Covid-19 pandemic in halting the research. But much of the work was focused on preventing outbreaks of other pathogens.

The James Webb Space Telescope identified the lights in the distant planet’s atmosphere, which could not be seen by earlier telescopes or spacecraft.

States have been told that they can no longer use grants that were funding infectious disease management and addiction services.

A 281-page spreadsheet obtained by The Times lists the Trump administration’s plans for thousands of foreign aid programs.