The federal Food and Drug Administration has issued a warning letter to the maker of the Brazilian Blowout Acai Professional Smoothing Solution, alleging the product contains a chemical that can be harmful if users follow the instructions on the label.

Sold and used in professional beauty salons, Brazilian Blowout is made by GIB LLC of North Hollywood.

In an Aug. 22 warning letter, the FDA said the product contains  methylene glycol, the liquid form of formaldehyde, which can be harmful “when hair treated with the product is heated with a blow dryer and then with a hot flat iron” in accordance with the product label’s instructions.

The FDA said tests showed the levels of methylene glycol ranging from 8.7 percent to 10.4 percent. It cited the company for misleading customers because the product’s label claims it contains “No Formaldehyde” or is “Formaldehyde Free.”

“This declaration renders your product misbranded because it is a false and misleading statement,” the FDA letter said.

Formaldehyde can cause eye injuries and respiratory ailments, the FDA letter said. It gave the company 15 days to correct the violations.