Harrison Schmitt, the Last Man to Walk on the Moon, Was Allergic to Moon Dust—Warns Others May Be Too

The last man to walk on the Moon—NASA astronaut Harrison Schmitt—suffered from an allergic reaction to Moon dust, and he has warned that other future visitors may too.

Schmitt was speaking at the Starmus Festival held in Zurich, Switzerland, last month when he started talking about his experience of walking on the Moon. The 84-year-old, who was part of the Apollo 17 mission, landed on the lunar surface on December 11, 1972.

Harrison Schmitt
Harrison Schmitt NASA

Schmitt was a geologist and was responsible for collecting samples from the Moon, including Troctolite 76535, which NASA says is "without doubt the most interesting sample returned from the Moon."

The dust got stuck to the suits, boots and tools of Schmitt and fellow astronaut Eugene Cernan, and was transported back into the lunar module. When he took his helmet off, Schmitt became congested.

According to the U.K.'s Daily Telegraph, he told the Starmus audience about his experience of inhaling Moon dust: "First time I smelled the dust I had an allergic reaction, the inside of my nose became swollen, you could hear it in my voice. But that gradually went away for me, and by the fourth time I inhaled lunar dust I didn't notice that.

"Whereas a flight surgeon taking suits out of the Apollo 17 command module, after we had splashed down, he had such a reaction that he had to stop doing what he was doing."

Schmitt says there should be a better understanding of how people react to Moon dust. NASA recently announced the first manned mission to the Moon since the Apollo mission was cancelled. Named Artemis, the space agency is hoping to put astronauts to the lunar surface by 2024—including the first ever woman.

Harrison Schmitt
Harrison Schmitt taking samples on the surface of the Moon during the Apollo 17 mission. NASA

"For some individuals we need to find out whether they are going to have a reaction, if they are going to be exposed chronically to Moon dust," Schmitt is quoted as saying. "Now my suggestion is don't ever let them be exposed to lunar dust and there are many engineering solutions since I was flying to keep dust out of the cabin, to keep it off the suit. It's going to be primarily an engineering problem."

This is not the first time Schmitt has spoken about his reaction to Moon dust. He called for an understanding of it in an interview with Wired in 2005: "Dust is the No. 1 environmental problem on the Moon," he told the magazine. "We need to understand what the [biological] effects are, because there's always the possibility that engineering might fail."

Eugene Cernan
Eugene Cernan in the lunar module covered in dust after walking on the Moon. NASA

Speaking to NPR two years later, he said: "This is unique dust. It is not like the dust that we are trying to keep out of our houses. I didn't know I had lunar-dust hay fever."

The potential health risks posed by Moon dust were recently studied by scientists, who found that long-term exposure to lunar dust may cause problems for astronauts on long duration missions. Publishing their findings in the journal GeoHealth, they found lunar dust caused cell death and DNA damage to lung cells.

"Clearly, avoidance of lunar dust inhalation will be important for future explorers, but with increased human activity on the Moon it is likely that adventitious exposure will occur, particularly for individuals spending long periods of time on that body. A detailed understanding of the health effects of lunar dust exposure is thus important, and further defining the cellular and biological impact of materials from various parts of the lunar surface is warranted."

Schmitt is one of only four living people to have walked on the Moon—the others are Buzz Aldrin, David Scott and Charles Duke. After leaving NASA in 1975, he entered the world of politics, becoming a senator in 1977. He has also been a prominent climate change denier, and resigned from the Planetary Society in 2008 over its policies on Mars and stance on what he calls the "global warming scare."