Can Meteorites Make People Sick?

On Monday, the Associated Press reported that a meteorite impact high in the Peruvian Andes left a 16-foot-deep crater in the ground. It struck midday Saturday, preceded by a loud explosion and fireball.

Local residents complained of headaches and nausea, along with a strange odor, soon after the space rock crashed to Earth. Policemen sent to investigate were themselves sickened and had to be hospitalized.

Were the two events connected? Can meteorites make you sick?

• Click here to view video of the impact site.

Meteorites start out in space as "meteoroids," which are often just grains of dust or dirt. Many of these specks of dust originate from the tails of comets and rain down as the Earth's orbit passes through or near the path of a comet.

When a meteoroid enters the Earth's atmosphere, it becomes what we call a "meteor." Friction with the air causes it to heat up and dissolve, creating the glowing streak of light we associate with shooting stars. Most meteors vaporize about 50 miles above the Earth's surface.

If, however, a meteor is large enough to survive the plunge to Earth and actually hits the ground, it earns the title of "meteorite."

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Made of either metal — iron and nickel — or stone, meteorites are usually pieces of some bigger body.

They can even be pieces of other planets or moons: Large meteorites colliding into a planet or moon can eject so much debris that pieces escape the body's gravity into space. This is how Martian meteorites have ended up here on Earth.

So can radiation or gas from meteorites affect people nearby?

"I don't know of any cases of that happening," said Richard Binzel, professor of planetary sciences at MIT.

Binzel said meteorites are not significantly radioactive. The Earth and other bodies with magnetic fields are surrounded by doughnut-shaped radiation belts — in Earth's case, these are known as the Van Allen belts.

Although incoming meteorites usually pass through the Van Allen belts, the speed at which they hurtle toward Earth — about 19 miles (30 km) per second — means that the dose of radiation they receive while in the belts is, according to Binzel, "irrelevant."

Comets are generally composed of frozen gas and liquid, but not solid meteorites.

"Meteorites that fall generally don't have much in the way of volatile gas," said Binzel.

Any gas contained within them would be in minuscule amounts.

"Meteorites from Mars have trapped pockets of the Martian atmosphere, which is how we identify them," said Binzel.

But, he added, the gas in these pockets must be measured microscopically.

What about dirt, dust and ash thrown into the air by the meteorite striking the ground? Could that make people ill?

Yes, said Binzel, "but the extent is probably minimal" because you would have to very close to the impact site when it happened.

In that event, a more troublesome danger would be from large pieces of debris falling upon you. Air quality would not be as much of a concern.

Ed Scott, professor of planetary sciences at the University of Hawaii, agreed.

"If you have a big impact [like the one] that created the Barringer crater in Arizona," said Scott, referring to the mile-wide pit blasted into the southwestern desert 50,000 years ago, then the iron and nickel in a metal meteorite or sulfur in a stone meteorite could vaporize to create poisonous gas.

But again, the gas would be the least of one's problems from such a massive collision: seismic waves, shock waves and airborne debris would be more immediate worries.

OK. What if the impact of a meteorite released gases trapped below ground? Could that happen?

"I guess technically, but those things don't happen very often," said Scott, adding that he knew of no instances of such an event occurring.