This is taken from the FDA website as well.
Sunless Tanning Sprays and Lotions
Sunless tanning delivers a faux glow by coating your skin with the chemical dihydroxyacetone (DHA). DHA interacts with the dead surface cells in the epidermis to darken skin color and simulate a tan, and the result usually lasts for several days.
While the FDA allows DHA to be "externally applied" for skin coloring, there are restrictions on its use. DHA should not be inhaled, ingested, or exposed to areas covered by mucous membranes including the lips, nose, and areas in and around the eye (from the top of the cheek to above the eyebrow) because the risks, if any, are unknown.
LINK:
http://www.fda.gov/cdrh/tanning/tanningproducts.html#2