When waoking withhydrofluoric acidyou should be careful.  Here are some precautions:(1)Never use hydrofluoric acid(HF) when working alone or after hours. Always ensure that knowledgeable laboratory personnel have been alerted and at least one is in the general vicinity. (2)All lab personnel, not just those who will be using HF, should be informed of the dangers of this chemical and the emergency procedures necessary in case of an accident. A sign should be posted to alert people that work with HF is in progress. (3)All persons who will be using HF must be made aware of its properties and trained in proper procedures for use and disposal. (4)Laboratories which keep or use HF gas or concentrated solutions (>1% HF) should have emergency procedures on hand as well as an MSDS. (5)Laboratories which keep or use HF gas or concentrated solutions (>1% HF) must have an operational safety shower and eye wash in their laboratory.Before beginning any procedure involving HF, make sure the access to the emergency shower and eyewash is unobstructed. (6)Undergraduate students should never be given the task of mixing Hydrofluoric Acid solutions. Only experienced persons familiar with its properties should handle the concentrated acid. (7)Clean up all spills promptly. (8)Purchase  HF in limited quantities. Keep as little on hand as possible (3 month or less supply). (9)When working with HF or concentrated HF solutions (> 1%): work in a fume hood with the sash as low as possible. Wear goggles and a face shield. Wear a long-sleeved, buttoned lab coat, pants or long skirt, and closed-toe shoes. Wear Neoprene or Nitrile (22mil) gloves or other Hydrofluoric Acid resistant gloves (HF burns around the fingernails are extremely painful, difficult to treat, and may require surgical removal of the nail). A chemically resistant apron is also recommended. (11)Double gloving is highly recommended. Make sure your gloves have no pin-holes. (12)Do not leave tongs, stirrers, etc., which have been contaminated with HF in fume hoods where other people may pick them up or otherwise come into contact with them. (13)Any exposure to HF must be medically evaluated. (14)Any unattended containers must be labelled. If it is not feasible to do this, and containers must be left in the laboratory fume hood unattended by the HF user, place a placard or sign in the fume hood indicating the hydrofluoric acid hazard. (15)When the work has been completed and personal protective equipment has been removed, wash hands thoroughly with soap and water. (16) Properly dispose of contaminated disposable gloves, aprons, etc in a plastic container and close it so it is spill proof. All waste containers must be labeled with a hazardous waste label with the chemical name written out. (17)The principle investigator shall supply a CHP for the processes involving HF to affected employees and verify that they understand it. (18)Employees should understand the health and physical hazards of HF. The ability of HF to inflict damage without initial pain should be emphasized.

Solutions with concentrations > 50% may release hazardous concentrations of hydrofluoric acid vapor under conditions of poor ventilation and require respirator use. If employees wish to use respirators when using HF, such respirators shall only be obtained after proper training in respirator use. The principle investigator shall ensure that only employees who have received respirator training and have received appropriate medical exams by an Occupational Health Physician are allowed to wear respirators. Persons wearing respirators must also be fit tested for their respirator annually.

Summary of HF safety: (1)HF is an extremely dangerous chemical, and can cause death from a skin exposure of less than 3% of body area. Special training, preparation, Personal Protective Equipment, and handling precautions are needed at all times. (2)This training is not a substitute for medical advice, Risk Assessments, Chemical Safety Data Sheets, or any other professional service that needs to be used before dealing with HF. (3)If you are exposed to HF seek medical attention immediately, even if you do not feel pain. It may take up to 24 hrs to feel the pain from <20% HF exposure. (4)In order to warn and protect others from the hazard of HF, a warning sign indicating the use of hydrofluoric acid should be posted.