Subway in the US 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 under way before the petition was launched.

“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 US 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 is also used to make yoga mats and shoe rubber.

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

Although the ingredient is used in other food products, Hari said she targeted Subway because of the healthy image it projects.

As Americans pay closer attention to what they’re eating, 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.

Subway has more than 39,000 locations worldwide. It is based in Milford, Connecticut.