Chlorine Trifluoride Exposure Testing and Oxidizer Reactivity Results

Chlorine trifluoride (ClF₃) was first synthesized in the 1930s and is one of the most oxidizing and reactive halogen fluorides known. In fact, with the exception of elemental fluorine, ClF₃ may represent one of the most oxidizing and reactive materials in existence. Active research and commercial use of ClF₃ began in the late 1940s, and ClF₃ has been utilized in such diverse applications as military weapons usage, rocket fuel oxidant, nuclear fuels processing, oil well rod cutting, mineral analysis, and electronics manufacturing equipment cleaning. Such fluoride compounds present significant toxic, oxidizing, highly reactive, and environmental challenges in their manufacture, delivery, customer use, handling, disposal treatment, and emergency response. Air Products has been the primary manufacturer of ClF₃ in North America for about 40 years, and ClF₃ represents one of the strongest oxidizing and highest reactivity materials that Air Products handles worldwide. However, little information has been available in public literature or the industry regarding its oxidizing potential and reactivity strength with specific materials it may routinely or accidentally come in contact with. Therefore, Air Products conducted extensive release testing to expose various materials of construction (metals, plastics, and elastomers), building materials, personal protective equipment, and other common materials to both vapor and liquid phase releases of ClF₃. This paper discusses the synthesis, hazards, varied uses, and major incidents involving ClF₃. For example, one major ClF₃ liquid spill accident from the 1960s is discussed where an eyewitness stated, “The concrete was on fire!” The paper details controlled release exposure testing methods Air Products employed, results, and lessons learned regarding improved handling and usage recommendations for ClF₃ suppliers and customers. For example, a significant potential hazard was discovered regarding use of a safety shower if a person's clothing was exposed to ClF₃ liquid, which caused Air Products to change their Material Safety Data Sheet and Product Safety hazards training.