Lifeguards need to protect their skin from the sun when they’re poolside and landscapers should shield themselves while they’re getting dirty on the job.

Here’s another occupation with a high amount of exposure to ultraviolet light from the sun: aircraft pilot. A recently released study shows that an hour spent in a turboprop airplane cockpit flying at 30,000 feet equals about 20 minutes in a tanning bed. Aircraft windshields do not fully block UV-A rays, which can cause skin cancer.

In addition, flying elevates UV exposure because radiation levels are greater higher in the atmosphere. The researchers say that at an altitude common for commercial flight, UV radiation may be double its level on the ground.

To get a better idea of how in-aircraft sun exposure affects pilots, California researchers reviewed numerous studies previously done on the topic, taking an overview look at the data in search of trends. In addition to reviewing the data on pilots, they also looked at statistics for aircraft crew members in jobs that require a significant amount of time in the cockpit.

The researchers honed in on these people’s risk of developing melanoma, the most deadly form of skin cancer. Analyzed together, data from 19 studies show that the rate of melanoma cases among pilots and cabin crew is twice as high as the rate in the general population.

They also found a higher rate of death from melanoma among people in these occupations. Forty-two percent more pilots and cabin crew die of melanoma than do people in the general population.

Experts advise pilots to wear sunscreen and sun-protective clothing to help avoid skin cancer. They also should get regular skin checks. After all, melanoma is nothing to mess around with.