Yes spray tans are carcinogenic and spray tans can cause cancer in some people.
Spray tans contain a chemical known as dihydroxyacetone which is also known as DHA.
That chemical can cause cancer in some people because it can cause genetic mutations and wreak havoc on human DNA.
If you have anyone in your family that has had or has cancer then it would be best to avoid use of spray tan chemicals or sprays.
However as long as you're overall healthy and have no cancer history in your family then you may or may not get cancer just from spray tanning.
A lot of stuff that humans put on their body or even consume could cause cancer but cancer is rare and not everyone gets cancer from all those cancer causing chemicals.