Phosphoric acid.

May also be known as orthophosphoric acid. It is a corrosive acid. Phosphoric acid is used in fertilizers, livestock feed, soaps, polishes, dyes and waxes. It is also used in soft drinks to make them more flavorful. It also slows the growth of molds and bacteria in sugary substances.

Overexposure to Phosphoric acid can cause dermatitis, eye pain and tearing, blurred vision, difficulty swallowing, shortness of breath, wheezing, coughing, irritation to the nose and throat and gastrointestinal problems. It may also cause bronchitis.

This is different than excessive consumption of phosphoric acid in drinks. This can include low bone density, dental/tooth enamel erosion and even kidney disease.