NEW YORK (AP) — Subway says it's in the process of removing a chemical from its bread as part of an ongoing effort to improve its recipes.

The announcement comes after a popular food blogger launched a petition this week asking the sandwich chain to stop using the ingredient, called azodicarbonamide. A representative for Subway says the change was underway before the petition was launched, but did not immediately provide details on when it started or when it would be complete.

"The complete conversion to have this product out of the bread will be done soon," Subway said in a statement, without providing further details.

Vani Hari, who runs FoodBabe.com, has targeted other food companies including Kraft and Chick-fil-A for the chemicals in their products.

In the latest petition targeting Subway, Hari noted that the azodicarbonamide used in its bread "as a bleaching agent" is also used to make yoga mats and shoe rubber. The petition noted that Subway doesn't use the ingredient in its breads in Europe, Australia or other parts of the world.

Although the ingredient is used in other food products, Hari said she focused on Subway because of the healthy image it tries to project. Subway has endorsement deals with Olympic athletes.

"This is not eating fresh!" Hari's petition said.

On Tuesday, Subway's Facebook page was filled with comments regarding the chemical.

As Americans pay closer attention to what they eat, food companies have worked to market their products as natural. But companies have also come under growing pressure to remove chemicals people find questionable. That pressure has been heightened by consumers' ability to voice and share their concerns online. Last year, for instance, PepsiCo said it would remove an ingredient that had been linked to a flame retardant from its Gatorade drinks.

PepsiCo also said its decision was not a response to an online petition that had called for it to remove the ingredient.

Subway, which is privately held, says it has more than 41,000 locations worldwide. It is based in Milford, Conn.