Spray tanning has been considered a safe alternative to sun tanning, but a new investigation reveals sunless tanning sprays might not be risk-free after all.

ABC news reports the sprays contain a chemical, called dihydroxyacetone (DHA), that has been shown in scientific studies to cause genetic mutations when applied to cells in a dish.

No studies have been conducted in humans, so it's not clear whether genetic changes would occur in people, or whether the changes would pose health risks.

However, experts are calling the findings concerning, and called for more research on spray tanning.

"These compounds, in some cells, could actually promote the development of cancers or malignancies," Dr. Rey Panettieri, a toxicologist and lung specialist at the University of Pennsylvania, told ABC news. "And if that's the case then we need to be wary of them."

The Food and Drug Administration has approved DHA for external use, meaning it should not be inhaled or ingested, or applied to the lips. The FDA also says the chemical should not be used in the eye area.

But the agency approved DHA when it was used in tanning lotions, and has not investigated the safety of its use as a spray in tanning booths, ABC news says. In fact, such tanning booths which offer "all over" spray tans are not FDA approved.

Some experts are particularly concerned about the potential for DHA to cause lung cancer if inhaled.

There is also evidence that a small amount of the spray may be absorbed into the body, according to ABC news. Previously, experts had thought the product interacted only with dead skin cells.

When using spray tans, the FDA recommends consumers protect their eyes and mucous membranes, such as the mouth and nose, and avoid inhalation.

Many workers at tanning salons that offer the sprays were misinformed about the safety to DHA, and did not offer proper protection to their customers, ABC's investigation revealed. In response to the investigation, the tanning industry says it will provide new training to its employers, and make sure customers are aware of the FDA recommendations.