HF is a unique inorganic acid. The major route of occupational exposure in research labs is skin contact with HF solution or droplets. The fluoride ions are very rapidly absorbed through the skin and eyes and cause systemic toxicity.
HF progressively releases fluoride ions and the ‘free fluoride ions’ penetrate and spread into the deepest tissues, resulting in liquefactive necrosis (also known as colliquative necrosis, tissue death that liquefies the affected cells), hypocalcaemia (low calcium levels), hypomagnesaemia (low magnesium levels), and hyperkalemia (high potassium levels). The liquefactive necrosis mechanism differentiates HF from other strong acids which cause damage via the ‘free hydrogen ions’, thus causing coagulation necrosis with precipitation of the tissue proteins. Guidelines for the management of cutaneous, inhalation, ingestion, and ophthalmic burns from HF exposures are described by Hatzifotis, et al (2004). Injury and illness prevention is the most significant part of HF management in research labs because internal damage can occur before symptoms appear.