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Vesuvius Erupted, but When Exactly?

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Vesuvius Erupted, but When Exactly?

When Mount Vesuvius erupted in A.D. 79, fiery avalanches of ash and pumice assaulted Pompeii, displacing some 15,000 inhabitants and killing at least 1,500 more. Volcanic debris “poured across the land,” wrote the Roman lawyer Pliny the Younger, and blanketed the town in a darkness “like the black of closed and unlighted rooms.” Within two days Pompeii had vanished, leaving little more than a legend until 1748, when the chance discovery of a water line prompted the first deliberate excavation.

In his late-18th-century travelogue “Italian Journey,” Goethe observed that no calamity in history had given greater entertainment to posterity than the eruption that had buried Pompeii. For scholars and armchair archaeologists, that entertainment has involved wrangling over pretty much every facet of the disaster. They still can’t agree on the day Vesuvius blew its top, the height of the umbrella-shaped cloud or the length and the aggression of the blasts. Two new research projects add kindling to those embers.

A report published by the Archaeological Park of Pompeii resurrected the once widely accepted belief that the cataclysm began to unfold on Aug. 24, the date put forward by Pliny, who was 17 when he witnessed the event from a villa across the Bay of Naples. His letters to the historian Tacitus, written more than 25 years after the fact, are the only surviving firsthand account and the only documents that offer a precise date.

Pliny the YoungerCredit…DeAgostini/Getty Images

We no longer have the original letters, only translations and transcriptions of copies, the first of which was made in the fifth century A.D. “Many manuscripts of Pliny’s letters came down to us with differing dates,” said the classicist Daisy Dunn. Her 2019 biography of Pliny, “The Shadow of Vesuvius,” is the definitive guide to him and his uncle, the naturalist Pliny the Elder, who died during the eruption. “Aug. 24 was chosen as the most secure on textual grounds,” Dr. Dunn said.

In sticking by Pliny, the park walked back some of the recent enthusiasm for Oct. 24 as a possible start date for the eruption, a theory that had been fueled by the 2018 discovery of a scrap of graffiti on a wall of the site’s freshly excavated House of the Garden. The charcoal scrawl records a date that translates to Oct. 17 in the modern calendar, suggesting that the eruption might have occurred after this time. The find, which did not specify a year, seemed to corroborate other unearthed clues that pointed to cooler weather than is typical in August: remnants of unripe autumnal fruits such as chestnuts and pomegranates; heavy wool clothing found on bodies; wine in sealed jars, indicating that the grape harvest was over; and wood-burning braziers in homes.

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Massimo Osanna, general director of the park at the time of the discovery, was convinced that the graffiti was idly doodled a week before the explosion. “This spectacular find finally allows us to date, with confidence, the disaster,” he said. Dr. Dunn found it improbable that Pliny would have forgotten such a momentous date; still, she said, “in my view, the traditional date of Aug. 24 is just too early in the year to be accurate.”

The park’s recent about-face from October to August relied in part on a forensic analysis of Pliny’s letters by Pedar Foss, a classicist at DePauw University in Indiana. For his 2022 book, “Pliny and the Eruption of Vesuvius,” Dr. Foss examined 79 early hand-copied manuscripts of the letters and mapped out how textural errors had been compounded. He concluded that a simple scribal mistake, made in the 1420s, of switching a “u” for an “n” had resulted in an incorrect eruption date of Nov. 1. The error appeared in the second print edition of Pliny’s letters, in 1474, and gave rise to further misreadings, misunderstandings and misuses.

By the 20th century, seven different possibilities were in circulation — eight, counting Nov. 9, which Mark Twain casually proposed in “Innocents Abroad,” his 1869 travel narrative. “Those many options gave the appearance of doubt concerning what Pliny actually wrote but, upon examination, I was able to explain away each of the mistaken alternatives,” Dr. Foss said.

He also explained away each of the archaeological alternatives to Aug. 24, some of which he believes fail based on the evidence; some, on the basis of faulty reasoning. He argued that the pomegranate rinds were used for dyeing, not eating; that the Romans commonly used braziers for cooking, not just heating; that wool clothing was standard gear for Roman firefighters; and that Roman agricultural and storage practices allowed for the preservation of fruits beyond their natural harvest seasons.

As for the House of the Garden doodle, on Oct. 12, 2023, researchers commissioned by Dr. Osanna’s successor, Gabriel Zuchtriegel, left their own charcoal message on the same wall on which the graffito appeared. Ten months later — on Aug. 24, 2024 — the text was still perfectly legible. “The inscription could have been put on the wall during October of any number of previous years,” Dr. Foss said.

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So much for dating the disaster with confidence.

Claudio Scarpati, a volcanologist at the University of Naples Federico II, favors the traditional date. “In my mind, the eruption occurred in August, on a sunny day,” he said. Dr. Scarpati is the lead author of two recent studies of the catastrophe published in The Journal of the Geological Society. One offered an hour-by-hour reconstruction, extending the chronology from the previously estimated 19 hours to 32 hours. The other revealed a dynamic sequence with 17 distinct “pyroclastic density currents,” many of them previously undocumented.

Pyroclastic currents are hot, swift-moving mixtures of volcanic particles — ash, pumice lava fragments and gas — that flow according to their density in relation to the surroundings. Dr. Scarpati said that contrary to popular belief, Pompeians were neither entombed by molten lava nor poisoned by gas. “No lava reached Pompeii, and the gas was predominantly vaporized water and, to a lesser extent, carbon dioxide,” he said. “According to our studies, the victims died primarily from asphyxiation caused by inhaling ash.”

To measure the distribution and the volume of the ash and the pumice layers, the team measured the thickness of the single layers over a 775-square-mile area around Mount Vesuvius. The deposits recorded dramatic, increasingly violent pulses from the volcano.

At noon on Day 1, Vesuvius began to eject a plume of rocky volcanic fragments and gas into the air, known as an eruption column. The mushroom cloud that Pliny observed at 1 p.m. was typical of what is now known as a Plinian eruption, in tribute to his richly detailed testament.

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Dr. Scarpati said that the first currents had flowed to the town of Herculaneum, west of Vesuvius, bringing intense heat that essentially roasted inhabitants and, in one documented case, turned human tissue into glass, a process known as vitrification. At Pompeii, south of the volcano, the currents were cooler, and only the final eight penetrated the town.

During the first 17 hours, Dr. Scarpati said, Pompeii was blanketed with pumice lapilli from the column, which fluctuated like a giant fountain through 12 distinct pulses. At 2 p.m., the volcano began to spew pumice mixed with gas. Over the next four hours, roofs began to cave in under the weight of the pumice lapilli, causing some supporting walls to crumble as well. After 17 hours, the debris in Pompeii was up to nine feet thick. Enough was ejected to bury Manhattan roughly 450 feet, or 45 building stories, deep.

The eruption peaked when the column reached its maximum height of 21 miles, at about 1 a.m. on Day 2. “The column rose as long as its density was lower than that of the air, like a balloon,” Dr. Scarpati said. At daybreak, enormous amounts of fine ash and pumice collapsed the eruptive column, forming pyroclastic currents.

During a brief lull, Pompeians presumably tried to flee the town. Then, just after 7 a.m., the 13th and most lethal current struck — a thick concoction of ash was disgorged for nine hours, spreading detritus 16 miles across the plain and into the Lattari Mountains. In Pompeii, many victims of the volcano were found in the streets encased in this layer.

Around 4 p.m., the magma in the volcano’s conduit interacted with groundwater, causing the magma to break up into fine ash. No human remains were found in any of the layers after the 13th, suggesting to Dr. Scarpati that the morning’s devastation left no survivors. The eruption ceased at 8 p.m.

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Paul Cole, a volcanologist at the University of Plymouth in England who was not involved with the project, said, “The work places a finer timeline on the events of 2,000 years ago, and also provides fresh evidence for how the hazard from such large, explosive eruptions can change even during the event.”

Rumpus involving Vesuvius may go on endlessly, but unlike Pliny’s letters, the geological history of the eruption seems to have been written in stone.

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Tuberculosis outbreak reported at Catholic high school in Bay Area. Cases statewide are climbing

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Tuberculosis outbreak reported at Catholic high school in Bay Area. Cases statewide are climbing

Public health officials in Northern California are investigating a tuberculosis outbreak, identifying more than 50 cases at a private Catholic high school and ordering those who are infected to stay home. The outbreak comes as tuberculosis cases have been on the rise statewide since 2023.

The San Francisco Department of Public Health issued a health advisory last week after identifying three active cases and 50 latent cases of tuberculosis at Archbishop Riordan High School in San Francisco. The disease attacks the lungs and remains in the body for years before becoming potentially deadly.

A person with active TB can develop symptoms and is infectious; a person with a latent tuberculosis infection cannot spread the bacteria to others and doesn’t feel sick. However, a person with a latent TB infection is at risk of developing the disease anytime.

The three cases of active TB have been diagnosed at the school since November, according to public health officials. The additional cases of latent TB have been identified in people within the school community.

Archbishop Riordan High School, which recently transitioned from 70 years of exclusively admitting male students to becoming co-ed in 2020, did not immediately respond to the The Times’ request for comment.

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School officials told NBC Bay Area news that in-person classes had been canceled and would resume Feb. 9, with hybrid learning in place until Feb. 20. Students who test negative for tuberculosis will be allowed to return to campus even after hybrid learning commences.

Officials with the San Francisco Department of Public Health said the risk to the general population was low. Health officials are currently focused on the high school community.

How serious is a TB diagnosis?

Active TB disease is treatable and curable with appropriate antibiotics if it is identified promptly; some cases require hospitalization. But the percentage of people who have died from the disease is increasing significantly, officials said.

In 2010, 8.4% of Californians with TB died, according to the California Department of Public Health. In 2022, 14% of people in the state with TB died, the highest rate since 1995. Of those who died, 22% died before receiving TB treatment.

The Centers for Disease Control and Prevention estimated that up to 13 million people nationwide live with latent TB.

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How does California’s TB rate compare to the country?

Public health officials reported that California’s annual TB incidence rate was 5.4 cases per 100,000 people last year, nearly double the national incidence rate of 3.0 per 100,000 in 2023.

In 2024, 2,109 California residents were reported to have TB compared to 2,114 in 2023 — the latter was about the same as the total number of cases reported in 2019, according to the state Department of Public Health.

The number of TB cases in the state has remained consistent from 2,000 to 2,200 cases since 2012, except during the COVID-19 pandemic from 2020 to 2022.

California’s high TB rates could be caused by a large portion of the population traveling to areas where TB is endemic, said Dr. Shruti Gohil, associate medical director for UCI Health Epidemiology and Infection Prevention.

Nationally, the rates of TB cases have increased in the years following the COVID-19 pandemic, which “was in some ways anticipated,” said Gohil. The increasing number of TB cases nationwide could be due to a disruption in routine care during the pandemic and a boom in travel post-pandemic.

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Routine screening is vital in catching latent TB, which can lie dormant in the body for decades. If the illness is identified, treatment could stop it from becoming active. This type of routine screening wasn’t accessible during the pandemic, when healthcare was limited to emergency or essential visits only, Gohil said.

When pandemic restrictions on travel were lifted, people started to travel again and visit areas where TB is endemic, including Asia, Europe and South America, she said.

To address the uptick in cases and suppress spread, Gov. Gavin Newsom signed Assembly Bill 2132 into law in 2024, which requires adult patients receiving primary care services to be offered tuberculosis screening if risk factors are identified. The law went into effect in 2025.

What is TB?

In the United States, tuberculosis is caused by a germ called Mycobacterium tuberculosis, which primarily affects the lungs and can impact other parts of the body such as the brain, kidneys and spine, according to the Centers for Disease Control and Prevention. If not treated properly, TB can be fatal.

TB is spread through the air when an infected person speaks, coughs or sings and a nearby person breathes in the germs.

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When a person breathes in the TB germs, they settle in the lungs and can spread through the blood to other parts of the body.

The symptoms of active TB include:

  • A cough that lasts three weeks or longer
  • Chest pain
  • Coughing up blood or phlegm
  • Weakness or fatigue
  • Weight loss
  • Loss of appetite
  • Chills
  • Fever
  • Night sweats

Generally, who is at risk of contracting TB?

Those at higher risk of contracting TB are people who have traveled outside the United States to places where TB rates are high including Asia, the Middle East, Africa, Eastern Europe and Latin America.

A person has an increased risk of getting TB if they live or work in such locations as hospitals, homeless shelters, correctional facilities and nursing homes, according to the CDC.

People with weakened immune systems caused by health conditions that include HIV infection, diabetes, silicosis and severe kidney disease have a higher risk of getting TB.

Others at higher risk of contracting the disease include babies and young children.

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Contributor: Animal testing slows medical progress. It wastes money. It’s wrong

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Contributor: Animal testing slows medical progress. It wastes money. It’s wrong

I am living with ALS, or amyotrophic lateral sclerosis, often called Lou Gehrig’s disease. The average survival time after diagnosis is two to five years. I’m in year two.

When you have a disease like ALS, you learn how slowly medical research moves, and how often it fails the people it is supposed to save. You also learn how precious time is.

For decades, the dominant pathway for developing new drugs has relied on animal testing. Most of us grew up believing this was unavoidable: that laboratories full of caged animals were simply the price of medical progress. But experts have known for a long time that data tell a very different story.

The Los Angeles Times reported in 2017: “Roughly 90% of drugs that succeed in animal tests ultimately fail in people, after hundreds of millions of dollars have already been spent.”

The Times editorial board summed it up in 2018: “Animal experiments are expensive, slow and frequently misleading — a major reason why so many drugs that appear promising in animals fail in human trials.”

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Then there’s the ethical cost — confining, sickening and killing millions of animals each year for a system that fails 9 times out of 10. As Jane Goodall put it, “We have the choice to use alternatives to animal testing that are not cruel, not unethical, and often more effective.”

Despite overwhelming evidence and well-reasoned arguments against animal-based pipelines, they remain central to U.S. medical research. Funding agencies, academic medical centers, government labs, pharmaceutical companies and even professional societies have been painfully slow to move toward human- and technology-based approaches.

Yet medical journals are filled with successes involving organoids (mini-organs grown in a lab), induced pluripotent stem cells, organ-on-a-chip systems (tiny devices with human cells inside), AI-driven modeling and 3D-bioprinted human tissues. These tools are already transforming how we understand disease.

In ALS research, induced pluripotent stem cells have allowed scientists to grow motor neurons in a dish, using cells derived from actual patients. Researchers have learned how ALS-linked mutations damage those neurons, identified drug candidates that never appeared in animal models and even created personalized “test beds” for individual patients’ cells.

Human-centric pipelines can be dramatically faster. Some are reported to be up to 10 times quicker than animal-based approaches. AI-driven human biology simulations and digital “twins” can test thousands of drug candidates in silico, with a simulation. Some models achieve results hundreds, even thousands, of times faster than conventional animal testing.

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For the 30 million Americans living with chronic or fatal diseases, these advances are tantalizing glimpses of a future in which we might not have to suffer and die while waiting for systems that don’t work.

So why aren’t these tools delivering drugs and therapies at scale right now?

The answer is institutional resistance, a force so powerful it can feel almost god-like. As Pulitzer Prize–winning columnist Kathleen Parker wrote in 2021, drug companies and the scientific community “likely will fight … just as they have in past years, if only because they don’t want to change how they do business.”

She reminds us that we’ve seen this before. During the AIDS crisis, activists pushed regulators to move promising drugs rapidly into human testing. Those efforts helped transform AIDS from a death sentence into a chronic condition. We also saw human-centered pipelines deliver COVID vaccines in a matter of months.

Which brings me, surprisingly, to Robert F. Kennedy Jr. In December, Kennedy told Fox News that leaders across the Department of Health and Human Services are “deeply committed to ending animal experimentation.” A department spokesperson later confirmed to CBS News that the agency is “prioritizing human-based research.”

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Kennedy is right.

His directive to wind down animal testing is not anti-science. It is pro-patient, pro-ethics and pro-progress. For people like me, living on borrowed time, it is not just good policy, it is hope — and a potential lifeline.

The pressure to end animal testing and let humans step up isn’t new. But it’s getting new traction. The actor Eric Dane, profiled about his personal fight with ALS, speaks for many of us when he expresses his wish to contribute as a test subject: “Not to be overly morbid, but you know, if I’m going out, I’m gonna go out helping somebody.”

If I’m going out, I’d like to go out helping somebody, too.

Kevin J. Morrison is a San Francisco-based writer and ALS activist.

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A push to end a fractured approach to post-fire contamination removal

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A push to end a fractured approach to post-fire contamination removal

The patchwork efforts to identify and safely remove contamination left by the 2025 Eaton and Palisades fires has been akin to the Wild West.

Experts have given conflicting guidance on best practices. Shortly after the fires, the federal government suddenly refused to adhere to California’s decades-old post-fire soil-testing policy; California later considered following suit.

Meanwhile, insurance companies have resisted remediation practices widely recommended by scientists for still-standing homes.

A new bill introduced this week by state Assemblymember John Harabedian (D-Pasadena) aims to change that by creating statewide science-based standards for the testing and removal of contamination deposited by wildfires — specifically within still-standing homes, workplaces and schools, and in the soil around those structures.

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“In a state where we’ve had a number of different wildfires that have happened in urban and suburban areas, I was shocked that we didn’t have a black-and-white standard and protocol that would lay out a uniform post-fire safety standard for when a home is habitable again,” Harabedian said.

The bill, AB 1642, would task the state’s Department of Toxic Substances Control with creating standards by July 1, 2027. The standards would only serve as guidance — not requirements — but even that would be helpful, advocates say.

“Guidance, advisories — those are extremely helpful for families that are trying to return home safely,” said Nicole Maccalla, who leads data science efforts with Eaton Fire Residents United, a grassroots organization addressing contamination in still-standing homes. “Right now, there’s nothing … which means that insurance companies are the decision-makers. And they don’t necessarily prioritize human health. They’re running a business.”

Maccalla supports tasking DTSC with determining what levels of contamination pose an unacceptable health risk, though she does want the state to convene independent experts including physicians, exposure scientists and remediation professionals to address the best testing procedures and cleanup techniques.

Harabedian said the details are still being worked out.

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“What’s clear from my standpoint, is, let’s let the public health experts and the science and the scientists actually dictate what the proper standards and protocol is,” Harabedian said. “Not bureaucrats and definitely not insurance companies.”

For many residents with still-standing homes that were blanketed in toxic soot and ash, clear guidance on how to restore their homes to safe conditions would be a much welcome relief.

Insurance companies, environmental health academics, and professionals focused on addressing indoor environmental hazards have all disagreed on the necessary steps to restore homes, creating confusion for survivors.

Insurance companies and survivors have routinely fought over who is responsible for the costs of contamination testing. Residents have also said their insurers have pushed back on paying for the replacement of assets like mattresses that can absorb contamination, and any restoration work beyond a deep clean, such as replacing contaminated wall insulation.

Scientists and remediation professionals have clashed over which contaminants homeowners ought to test for after a fire. Just last week, researchers hotly debated the thoroughness of the contamination testing at Palisades Charter High School’s campus. The school district decided it was safe for students to return; in-person classes began Tuesday.

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Harabedian hopes the new guidelines could solidify the state’s long-standing policy to conduct comprehensive, post-fire soil testing.

Not long after the federal government refused to adhere to the state’s soil testing policy, Nancy Ward, the former director of the California Governor’s Office of Emergency Services, had privately contemplated ending state funding for post-fire soil testing as well, according to an internal memo obtained by The Times.

“That debate, internally, should have never happened,” Harabedian said. “Obviously, if we have statewide standards that say, ‘This is what you do in this situation,’ then there is no debate.”

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