Belgium’s Fog of Death

Dale M. Brumfield
Oct 22, 2018 · 8 min read

Belgium’s Meuse River valley has long been an inviting tourist destination. The Meuse River meanders through northern France before taking an L-shaped path through Belgium, where it leisurely passes historic towns, striking abbeys and châteaux nestled among its extremely impressive scenery. From Belgium it then crosses into Holland, where its name changes to the Maas River.

But for almost five days starting December 1, 1930, this scenic valley was occupied by a creeping horror — a wet, impenetrable and extremely toxic fog, centered at the town of Engis. Before it lifted completely on December 6 1930, 65 residents of Engis and several other towns, who had been exposed to the dense clouds, had died horrible, choking deaths. Hundreds of others were stricken with mysterious respiratory illnesses, and thousands of cattle, horses and other farm livestock asphyxiated and died in the fields “like flies sprayed with poison gas.”

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Meuse Valley residents were thrown into terrified confusion by this lifeless, mysterious and deadly miasma that reduced visibility to about three meters (or arms’ length) and caused blindness, nausea and horrific choking fits. Many locked themselves into their homes and chinked every crack with rags. Some even brought their farm animals indoors with them to save their lives.

At first, doctors and scientists were baffled, with come thinking the deadly fog could be a resurgence of the Black Plague, which wiped out between 75 and 200 million Europeans from 1347–1351. Since persistent fog was so uncommon to that region, with only five events of persistent fog greater than three days ever documented, superstitious townspeople feared that the fatal fog was Biblical end-time prophecy coming to fruition.

The devastation of World War I had driven many religious Europeans into even more mystic teachings, resulting in a flood of spiritualist books and media swamping Europe. Like Noah’s great flood, these believers saw the fog as the beginning of a “reign of terror” whose “floating poison” had been predicted by numerous seers down through the centuries.

And this wasn’t the first time that shadowy meteorological visitations had plagued this valley. In January, 1897, a sudden outbreak of an asthma-like illness among humans and animals accompanied a dense fog that settled for three days in the town of Huy, a few miles southeast of the 1930 outbreak.

In 1902 there was an epidemic called “fog asthma,” which was so severe the Belgian government investigated but found no reasons. Post-mortem examinations of cattle that died in the fog showed advanced pulmonary emphysema — normally a chronic condition.

In January, 1911, a toxic fog had also drifted through the same valley, taking several human lives but especially exacting great casualties among cattle, hogs and sheep, devastating the local economy. An investigation by a famed Belgian meteorologist named Felix Bertyn concluded that the deaths were most likely attributable to some substance of local origin contained within the fog.

At the same time, a British meteorologist named W.T. Russell studied 27 years of notorious London-area fogs and concluded that while fogs in mild temperatures had almost no ill health effects, those fogs in low temperatures were attended by a marked increase in adult respiratory death rates.

In fact, Native American lore at the time recalled “Pogonips,” which were unusual ice fogs of the upper mid-west United States. These fogs were accompanied by extremely low temperatures, and Native Americans refused to go out in them as the needle-like ice crystals were believed to be fatal.

None of these precedents solved or even explained the mystery of the murderous 1930 Meuse Valley fog. At the time of the Meuse fog, other dense fogs had prevailed over vast swatches of Western Europe, with almost no ill effects.

So what made the Meuse fog so deadly?

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Residents resorted to their WWI-era gas masks for protection against the fog. (12–6–1930 Miami Sentinel)

On December 1, as the fog first rolled into the town of Engis and other localities, very little attention was paid to it. But after a few hours, after residents began coughing and choking almost non-stop, they went back into World War-era survival mode, locking themselves in their homes and not venturing out without a covering on their lower face.

Many dusted off their World War-era gas masks, wondering if there had been some sort of terrorist air raid. Others speculated that the Russians had unleashed some sort of revenge tactic as a form of payback for their lack of wartime loyalty.

Others wondered if stores of gases left buried in the valley after the war had suddenly been released. The lack of knowledge about the phenomenon, and the government’s ignorance and silence about it, caused wide-spread terror and dread.

As the hours wore on weary city and country doctors frantically worked 24-hour shifts answering desperate calls from people describing family members falling deathly sick at practically a moment’s notice. They had no explanation for what was happening — all they knew was in every instance the symptoms and conclusion was exactly the same: the patients came in from outside, started choking and coughing as of severe asthma or asphyxiation, then succumbed with death throes exactly as soldiers in the World War who were caught without masks in gas attacks.

In Engis, the Mayor was stricken ill but rallied to his feet to direct relief efforts. “The 3,000 inhabitants of my little town are terror-stricken,” he told the press. “Besides the dead, there are hundreds suffering with a strange disease …”

He added, however, in an effort to allay some of the more disturbing theories, that “I don’t think the theory of poison gas having been buried in the neighborhood and corrupting the air is sound.” He added that the fog had no smell and no apparent taste.

Identical deaths were also recorded at the towns of Liege, Flamelle Grande, Yvoy-Ramet, Hamay, Ampsin, Othel and numerous outlying areas within the valley.

One theory that quickly emerged was that fumes from the zinc works at Liege created the tragedy, but it was proven that the plant had been closed for months prior to the fog.

The Black Death theory was first floated by a renowned British scientist, Professor J.B.S. Haldane, who said “I don’t think the epidemic was created by war gas, because deaths have occurred in different villages.” He also theorized that recent flooding in the Meuse Valley may have somehow contributed to the illnesses.

Other British scientists believed that the deaths were due to a particularly virulent strain of air-borne influenza that could easily also be blown across the Channel or the North Sea and cause a similar epidemic in London or other large industrial centers. This possibility was suggested after a large number of cattle mysteriously died on a Yorkshire farm on December 7, 1930, despite the fact there was no fog in Yorkshire at that time.

By Dec. 7 the fog had lifted and residents who had fled the valley tentatively began returning. The public health commission, in positive PR mode, asserted that the deaths were caused by nothing more mysterious than weakened respiratory systems affected by the cold, smoke-laden fog. The next day, however, the President of the Belgian Red Cross, Prof. Nolf, declared at the opening of their Inquiry that the Meuse fog could not have killed anyone “had it been uncontaminated.”

American epidemiologists at the Hooper Foundation at the University of California Medical School somewhat concurred, stating that the deaths were due to infectious disease, possibly carried by the fog. Dr. J.C. Geiger stressed that the United States Public Health Service should “rigidly guard American ports against entry of the disease.”

The Belgian inquiry collected medical data by interviewing local doctors, victims who had experienced respiratory symptoms and family members of the deceased. Fifteen autopsies were performed, with tissue examinations and toxicological analyses of blood and organs. Results found only irritation of the mucous membranes, but all toxicological tests were negative, ruling out poison gas. Chemical analyses of valley soil deposits were completed to verify the composition of the fog, but results could not be linked specifically to it.

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Courtesy the 12–6–1930 Miami Sentinel.

By mid-December, 1930, the valley finally started to recover from the terrifying event. Funerals were finally held for the victims while hundreds more continued to recover in local hospitals. Queen of the Belgians Astrid of Sweden (pictured at left) visited the valley on the sixteenth, defying health officials by insisting on sitting bedside with the sick and dying.

It wasn’t until April, 1931 — after another brief episode of toxic fog that sickened several — when a probable hypothesis for the deadly fog was ascertained by the process of elimination. Heavier than usual concentrations of sulphur dioxide, brought on by the heavy domestic use of burning coal in the valley, was determined to be the culprit, although there was almost no solid evidence to support it.

The report concluded also that sulfur dioxide was the only pollutant that could have dispersed throughout the valley in high enough concentrations to exhibit such toxicity both in humans and animals. In addition, the unusual weather conditions promoted the production of sulfuric acid, which may have produced the asthma-like symptoms.

It was therefore concluded that the deaths and illnesses were not due to excessive Sulfur dioxide emissions alone, but to the combination of Sulfur dioxide within the fog.

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This conclusion seemed to be no comfort to the valley citizens most directly affected, so a scapegoat was found — the director of the Meuse Chemical Company in Liege was indicted on April 23, 1931 on a charge of “violating the laws regulating industries whose plants generate noxious gases.”

The Meuse Valley Fog of 1930 was one of the first examples of the lethal excesses of unchecked air pollution. As a result, a commission was appointed to assess then-current air pollution standards and make recommendations for improvement, with monitors added similar to those used in London.

However, even in light of the 67 total dead and hundreds permanently affected, it was ultimately agreed by the commission that air pollution was, in the end, “an unavoidable consequence of prosperity.”


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Dale M. Brumfield

Written by

Anti-death penalty advocate, cultural archaeologist, “American Grotesk” historyteller and author of 11 books. More at

Lessons from History

Lessons from History is a platform for writers who share ideas and inspirational stories from world history. The objective is to promote history on Medium and demonstrate the value of historical writing.

Dale M. Brumfield

Written by

Anti-death penalty advocate, cultural archaeologist, “American Grotesk” historyteller and author of 11 books. More at

Lessons from History

Lessons from History is a platform for writers who share ideas and inspirational stories from world history. The objective is to promote history on Medium and demonstrate the value of historical writing.

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