Possibly the most common use of nitric acid is in the production of nitrogen-based fertilizers. The US production per year reaches an approximate total of 11 million tons coming from about 65 manufacturing plants around the country. Meanwhile, in the UK, more than one million ton is produced annually.
Nitric acid is a colorless liquid which can become yellowish or reddish over time in storage due to the build up of nitrogen oxides. It is a highly corrosive liquid, a strong oxidizer, a poison and has the capacity to dissolve most metals.
Aside from being a main component in fertilizer production, nitric acid is also a very important component chemical in the manufacture of explosives, dyes, plastics, metallurgy and as a cleaning agent in food, dairy and brewing industries.
Nitric acid is such a very important chemical in many industries that although it is considered to be more dangerous than most chemicals in 6 out of 9 in the ranking systems, it is still produced in large volume and many of the people working in trades using nitric acid in its applications are put in occupational hazard. It is therefore important that safety information, proper handling training and other safety procedures are given to these workers.
Inhalation of nitric acid vapors may cause difficulty in breathing and, in fatal cases, may lead to pulmonary edema and pneumonia. Irritation of the nose, throat and respiratory tract, coughing and choking can be observed when someone accidentally inhales nitric acid vapors. Ingestion can also be very dangerous because of the corrosive property of nitric acid. It will cause instant burns and pains of the mouth, throat, esophagus and the rest of the gastrointestinal tract.
Nitric acid is an irritant and direct eye contact causes severe burns and may even result to permanent eye damage. Direct skin contact, on the other hand, causes pain, redness, and serious skin burns. Concentrated nitric acid solutions turn the skin yellow as a result of a reaction with keratin as well as ugly blisters.
Constant and long term exposure to vapors may result to erosion of the teeth and damage to the lungs. However, it is a seldom case that a long term exposure to nitric acid occurs because of the strong corrosive and high reactivity of the chemical. Patients with preexisting health conditions of the skin, eyes and cardiopulmonary system are more susceptible to the effects of the acid as well as exacerbate their conditions.
Apart from these health effects, the chemical properties of nitric acid also require special and secure handling to prevent reactions with others chemicals which can result to increase in flammability of combustible materials, fires and explosions. Leakage and spilling can also cause corrosion and other accidents.
Knowledge of the possible effects of nitric acid and the awareness of the safety precautions and proper handling should be an integral part of a company’s standard operating procedure and good manufacturing practices.
Workers should always wear protective clothing including chemical safety glasses and gloves. Gloves made from polyethylene, neoprene and butyl rubber are appropriate for handling up to 70% concentration of nitric acid solutions. Working area should also have good ventilation, more so when using concentrated form of the acid. Eye wash fountains and quick drench facilities must be within the direct vicinity of the work area.
It is the company’s responsibility to provide their workers with the proper protective outfit as well as the technical know-how of handling nitric acid. However, it then becomes the worker’s duty to always follow safety procedures and exercise extreme measures when dealing with hazardous chemicals such as nitric acid.