Twenty-six patients were transported to area hospitals late Wednesday evening for ammonia exposure after a leak occurred at a commercial building in Sterling, Virginia.

At approximately 8:36 p.m., Loudoun County Fire Rescue responded to the 22400 block of Sous Vide Lane in Sterling for reports of a gas leak. Officials later confirmed the leak was ammonia.

A representative for Cuisine Soultions Inc. told ABC News that employees were immediately relocated outside of the plant and that the leak was contained.

Four of the 26 patients were experiencing significant symptoms, according to officials.

This is a developing story. Check back for updates.