Phosphoric acid has low vapour pressures at room temperature and is not expected to present an inhalation hazard unless a mist is generated. Mists can probably cause irritation of the nose, throat and respiratory tract. A mechanic aboard a ship transporting 4000 tons of phosphoric acid was apparently exposed to phosphoric acid vapours three times for 20 minutes/exposure while attempting to repair a leak. Weakness, dry cough, chest pain and shortness of breath developed 7 to 8 hours after exposure. This worker still experienced symptoms of reactive airways dysfunction a year after the exposure. A co-worker with similar exposure died due to acute respiratory failure. The circumstances of the exposure are not well-defined and it is not known if the phosphoric acid was heated (for example by welding) while the workers were trying to repair the leak. Toxic phosphorus oxides can form upon heating phosphoric acid.

The degree of irritation caused by phosphoric acid depends upon the concentration of the solution and the duration of contact. Concentrated solutions can cause corrosive tissue injury or severe burns, based on animal information. Dilute solutions can probably cause mild to moderate irritation. There is no human information available.

The degree of irritation caused by phosphoric acid depends upon the concentration of the solution and the duration of contact. Concentrated can cause severe burns and permanent eye damage, based on animal information. Mists may cause eye irritation. There is no human information available.

There are no reports of occupational ingestion of phosphoric acid. There is one case report of an individual who died 19 days after ingesting an unspecified amount and concentration of phosphoric acid. Death was due to internal bleeding. Tissue death (necrosis) of the upper and lower digestive tract and the pancreas was evident at autopsy. Ingestion is not a typical route of occupational exposure.

SKIN: Repeated or prolonged contact may result in dermatitis (dry, red skin).

INHALATION: Pulmonary function was studied in a group of 131 phosphorus refinery workers employed for 3 to 46 years. Typical exposures included phosphoric acid, phosphorus oxides, fluorides and coal tar pitch volatiles. Airborne levels of phosphoric acid were not measured. No significant changes in pulmonary function were observed, once the effects of smoking on lung function were controlled. However, no conclusions can be drawn from this study due to limitations such as lack of exposure information and concurrent exposure to other chemicals.

There is no human or animal information available.

There is no human or animal information available.

There is no human or animal information available.

There is no information available.

Phosphoric acid can be absorbed into the body and enters the phosphate pool. Inorganic phosphate ion is naturally found in the body. It is excreted mainly in the urine.