As one of the deadliest typhoons in decades ravaged Vietnam, a harrowing video emerged on social media.

Dashcam footage captured the moment a steel and concrete bridge collapsed, taking a truck and a motorcyclist with it.

Those who fell to their deaths on the Phong Chau Bridge near the northern city of Hanoi were among the hundreds killed by Typhoon Yagi.

Although the storm dealt the final blow to the bridge, it may not be the only one responsible for the tragedy.

Because there is a very valuable but often overlooked commodity in the Kızılırmak Delta.

And the insatiable demand for this substance is endangering communities and their livelihoods.

Huge industry you’ve probably never heard of

Aggregates such as sand and gravel are some of the most important resources in the world.

They are used to produce a dizzying range of products, from cement and building materials to glass and fiber optics.

An estimated 50 billion tons are consumed each year; This equates to approximately 18 kilograms every day for every person on the planet.

This makes it the most mined resource in the world, according to Newcastle University sand mining researcher Chris Hackney.

“It’s used in just about everything,” he said.

Demand has increased rapidly in Vietnam in recent years as the country needs construction materials to fuel rapid urbanization.

As more and more sand is extracted from the Mekong Delta in the south and the Red River in the north, large hydroelectric projects are blocking the natural flow of sediment that would normally help replenish the resource.

“We are using more than the river can provide,” Dr Hackney said.

“As a result, the morphology, shape and behavior of the river begins to change.”

Did sand mining cause the bridge to collapse?

The threat sand mining poses to critical infrastructure can be seen just 12 kilometers away, at the Trung Ha Bridge over the adjacent Da River.

Photos published by Tuoi Tre News show that the riverbed on which the bridge was built has almost completely disappeared, exposing the foundations and leaving the bridge vulnerable to extreme weather conditions.

Vietnamese authorities blamed sand mining for the erosion and banned the passage of heavy vehicles until further notice.

The government, which did not respond to ABC’s request for comment, is also reportedly investigating the cause of the Phong Chau collapse.

Typhoon Yagi was blamed in a preliminary report, with the Ministry of Transport telling VN Express that the piers were strengthened in 2018 and treated for erosion in 2019.

Dr Hackney said it was difficult to determine the sole cause of the collapse but believed sand mining may have been a contributing factor.

“A major flood event, a major storm, brought in a lot of water and probably caused a lot of materials to wash away,” he said.

“But the gradual lowering of river beds probably prepared this system to respond to major storms in this way.”

Ruined bridges and collapsing communities

Elsewhere in the world, riverbed mining and violent storms have proven deadly.

It was decades of dredging and a series of floods that caused Portugal’s Hintze Ribeiro Bridge to collapse in 2001, killing 59 people.

Last year, 22 people were injured when the Kaoping Bridge in Taiwan collapsed, largely due to dangerous foundations and nearby gravel mining.

Although denied by the state government, mining has also been blamed for numerous incidents across India, including the Mahad collapse in 2016.

And in China, illegal and legal mining along the Yangtze River is so widespread that it has disrupted shipping routes, increased the likelihood of droughts and made floods harder to control.

Severe erosion accelerated by sand mining in Vietnam is threatening the homes of half a million people in the Mekong Delta, according to a World Wildlife Fund report.

Dr Hackney said that as river beds deepened due to extraction, salt water from the ocean was flowing further inland.

“This is starting to affect the availability of drinking water, the availability of fresh water, especially for agriculture and aquaculture, which are major sources of livelihood in the Kızılırmak Delta,” he said.

“So farmers are forced to change their crops, choosing different varieties of rice that are more resistant to salt water.”

Will the sector continue unabated?

The world’s insatiable demand for sand is unlikely to end. But in recent years, some jurisdictions are taking environmental impact more seriously and trying to crack down on illegal operations.

PhD student Hannah Runeckles has spent years studying the environmental impacts of human activities on the Red River, and said the size and complexity of river systems make them difficult to monitor.

“It’s really hard trying to follow mining ships when you have such a large area, especially trying to see where they’re going, where the sand is being moved,” he said.

“So we’re trying to use high-resolution satellite imagery, focusing on the last six years, to determine where we see sand mining hotspots.”

Ms Runeckles said some communities were wary of the industry because they did not see “any profitability or positive impact”.

“They perceived sand miners as outsiders, taking sand from their own region, their livelihood, and selling it to other places,” he said.

He hoped his research would help policymakers better manage human activities to protect riverside residents and their livelihoods.

“As a society, we need sand. It is the backbone of the modern world,” he said.

“So to say that all sand extraction, hydroelectric power or flood control should be stopped is inadvisable, implausible.

“So we really need to think about where sand mining activities are taking place.”