Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
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Understanding Potassium Nitrate Chemical of the Quarter by MS. AMY PARKER Chemical Engineer Hazardous Materials Division U.S. Coast Guard Headquarters 66 What is it? Potassium nitrate, also known as saltpeter, is a solid compound commonly used in fertilizer. Important macronutrients nitrogen and potassium, responsible for plant growth and Áower/seed formation, are readily available in potassium nitrate. In addition to being a good source of essential plant nutrients, potassium nitrate is also an efÀcient oxidizer. As such, it's been used in gunpowder, fireworks, and rocket propellants. How is it shipped? Potassium nitrate is a transparent or white powder or crystal. It can be shipped by being packaged into bags, in bulk containers, or in loose bulk form. Due to its chemical hazard (note its utility in explosives), it is required to transport the chemical according to the applicable regulations. Why should I care? Shipping concerns The primary concern with the shipment of potassium nitrate is its strong oxidizing potential. Its classiÀcation as a Class 5.1 oxidizing substance indicates it can generate oxygen when wet, causing or contributing to the combustion of other materials. Therefore, potassium nitrate should be stowed away from sources of heat or ignition in cool, dry places. It should be stowed away from foodstuffs and all readily combustible materials. Health Concerns Potassium nitrate can be harmful and cause irritation to the eyes, skin, and respiratory and gastrointestinal tracts. Eye and skin contact can lead to redness, itching, and pain. Inhaling potassium nitrate can lead Proceedings Winter 2012 | Spring 2013 to coughing and shortness of breath; ingestion may result in nausea, vomiting, and diarrhea. As with all nitrates, chronic exposure to potassium nitrate may cause anemia and have adverse effects on the kidneys. Fire or explosion concerns Although potassium nitrate is noncombustible, it will increase the Áammability of other combustible materials. Existing Àres are enhanced in the presence of potassium nitrate due to an increase in oxygen levels generated by potassium nitrate reduction. If potassium nitrate is involved in a Àre, it is imperative that emergency responders wear appropriate protective clothing such as gloves, boots, and coveralls in addition to self-contained breathing apparatuses. Carbon dioxide is not an effective means of controlling Àres involving potassium nitrate; therefore, large volumes of water may be required to extinguish the Àre. Ship stability should be given due consideration as signiÀcant amounts of water may accumulate. What is the Coast Guard doing about it? Transport of potassium nitrate as a bulk cargo is regulated under 46 CFR Part 148 and the International Maritime Solid Bulk Cargoes Code. When transported as a packaged cargo, it is shipped according to 46 CFR Part 173 and the International Maritime Dangerous Goods Code. About the author: Ms. Amy Parker is a chemical engineer in the Hazardous Materials Division at U.S. Coast Guard Headquarters. She is responsible for developing domestic and international regulations for the marine transport of solid bulk cargoes and representing the U.S. at the International Maritime Organization's subcommittee on dangerous goods, solid cargoes, and containers. www.uscg.mil/proceedings