Spray tans are pretty safe as long as you don't get a spray tan too often.
Getting a spray tan too often may lead to skin caner but in moderation spray tans are perfectly fine and safe.
I get a spray tan at least twice per year and have done so for around 10 years now and I'm still healthy.
Spray tans are considered to be much safer for your skin and health than tanning beds are but even spray tans when used in excess can cause skin issues and other health problems.
The spray tans have a potential to cause skin cancer in you get too many spray tans and overdo them.
The skin cancer can be caused by the chemical used in the spray tanning solution known as dihydroxyacetone (DHA) in tanning solutions, which interacts with dead cells on the skin's surface to evoke color change.
When used sparingly in safe amounts there's not much concern for skin cancer or other skin and health issues but when used too much it can cause skin cancer possibly and other health issues.
So don't overdo the spray tans for your skin but once in awhile it's perfectly fine to get spray tans done.