JACKSONVILLE, Fla. -- Hair salons across the country are being warned about smoothing and straightening products potentially containing formaldehyde.

The Brazilian Blowout and other brands of smoothing treatments were first questioned in October 2010, when employees at an Oregon salon reported difficulty breathing, nose bleeds and eye irritation when using the products.

Health officials in Oregon tested Brazilian Blowout and other brands and found trace levels of formaldehyde in the air at several salons, and significant amounts in the product itself.

Health alerts were issued in several states.

The U.S. Department of Labor's Occupational Safety and Health Administration has issued a nation-wide hazard alert and said it is "responding to complaints and referrals about possible exposure to formaldehyde."