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Welcome to Business Daily on the BBC, where we're going to South America, and we're going up in the world.

Good morning. My name is Leonardo Espos. Good morning. My name is Leonardo Espos. I've been working at Escondida for 10 years.

Caroline Abayay. I'm Caroline Abayi, and I've been at Skondida for 16 years.

Those are just two of the workers at Escondida, the largest copper mine in the world.

It's in Chile, and it's at 3,100 metres above sea level in the Andes Mountains.

That's over 10,000 feet up.

To give you an idea that's higher than the highest peak in Germany,

it's higher than Mount Olympus in Greece, and higher than anywhere in mainland Australia.

Leonardo and Caroline are among 150 million people worldwide who work at high altitude, generally defined by medics as 2,500 metres or above.

From Tibet to the Ethiopian highlands, people are toiling in conditions that could, in theory,

pose a threat to their health.

In South America, this isn't limited to people who work in minds.

Here's Marta Cabrera.

She's the president of the Latin American Association of Occupational Health.

There are other types of work that occur in high altitude,

going from, you know, construction and repair of roads, other public works,

the tourist centers, you know, the ski centers that are in high altitude.

We have everybody working at the borders crossings, like transportation in the international

routes that goes through high altitude.

We have some astronomical observatories.

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