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Policy for Safe use of Hydrofluoric Acid

PURPOSE: This policy establishes safe work procedures for personnel working with hydrofluoric acid (HF), a highly hazardous chemical. It outlines safe work practices and response in case of emergency to minimize health risks.

SCOPE:  This policy covers all university campuses including Morningside (MS), Lamont-Doherty Earth Observatory (LDEO), Medical Center (CUMC) and Nevis.

APPLICABILITY:  This policy covers users of HF, the researchers whose work presents the highest potential for exposure, Facilities workers and first-responders to incidents involving HF releases.

INTRODUCTION
The hydrofluoric acid is a clear and colorless corrosive liquid. HF is also available as gaseous material. All forms of HF can cause sever burns to tissue, which makes its handling and use, especially hazardous. HF easily dissolves glass and can attack enamels, pottery, concrete, rubber, leather, many metals and organic compounds. Upon reaction with certain metals, explosive hydrogen gas may be formed. HF has many industrial applications but in an academic environment it is normally used in small quantities for fabrication of electronic components, etch glass, biological staining, mineral digestion, etc. 

HF, though a weak acid, is physiologically a very potent chemical due to fluoride ions, which can bind with Calcium and Magnesium ions in the tissue. Concentrated HF, liquid or vapor, may cause sever burns, electrolyte imbalance, pulmonary edema and or life threatening cardiac arrhythmias. Even moderate exposure may rapidly progress to fatality if not treated promptly and properly. Symptoms of exposure may be delayed for several hours, therefore, immediate medical intervention; even in the absence of symptoms is necessary.

PROCEDURE

I. Working safely with HF 

  • Chemical Fume Hood: The safest place to work with HF is in a properly working chemical fume hood.  Before use, always check the fume hood is certified and working properly. Procedures involving even small quantities of dilute HF solutions must not be performed on the lab bench. Avoid older fume hoods with soapstone work surfaces.  Prevent contamination of the work surfaces by placing plastic trays or bench paper on the work surface before starting HF procedures.
  • Gloves: Working in a fume hood protects the worker from inhalation exposure, and, to a certain extent, splashes, but the hands are still vulnerable to HF exposure.  HF readily penetrates skin and becomes trapped under fingernails. Heavy neoprene or nitrile rubber (recall that HF attacks natural rubber) gloves are best for working with HF; however the increased thickness of the gloves reduces dexterity, increasing the possibility of spills.  Wear two pairs of nitrile exam gloves at a time, changing the outer pair often.  When working with larger quantities of HF in procedures that do not require as much dexterity, wear heavy nitrile or neoprene rubber gloves, with a nitrile exam glove worn under the outer glove.
  • Body Protection: When working with HF, wear clothing and personal protective equipment (PPE) that provides protection in the event of a spill: long-sleeved shirt, long pants, and closed shoes.  Always wear a lab coat, chemical-resistant apron and sleeves.  Do not wear shorts and sandals in laboratory. 
  • Eye Protection: Goggles, along with a face shield, should be worn when handling HF to prevent eye/face exposure.

II. Limitations on the Use of HF:
Hydrofluoric acid is an extremely hazardous material. Lab personnel should work in the buddy system and NO one be allowed to work alone. For safety reasons the use of hydrofluoric acid by the University staff or students should preferably be limited to office hours (You must discuss change in procedures with your supervisor). Only persons who have read and understood this document and who are suitably trained should be allowed to use this substance. Furthermore:

  • Do not eat, smoke, or drink where HF is handled or used. 
  • Wash hands thoroughly with soap and water after handling HF.
  • Inform any first responder called to deal with an incident involving HF about the hazards associated with this substance, and
  • Provided with appropriate protective gloves, a copy of this policy andSDS to the responder.

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III. Emergency Measures During Exposure to hydrofluoric acid
 
Avoid all type of exposure to HF. When working, pay close attention to the task at hand and do not allow yourself to become distracted.  Contact with dilute HF solutions may not produce immediate pain, but may result in severe burns without immediate treatment.

Skin Exposure Rapid decontamination is critical to minimizing/preventing injury.  If exposure occurs, remove contaminated clothing and immediately wash the affected area with copious amounts of water for 15 minutes.  Have someone else call for medical assistance during this time.  After washing the affected areas, apply calcium gluconate first aid gel.  Calcium gluconate binds HF and prevents it from penetrating deeper into tissues. This is critical.
  • Inhalation: Immediately remove victim to clean air until emergency personnel arrives on scene. Unlike external splashes, inhalation exposure is a serious medical emergency as it is more problematic because there are no immediate decontamination procedures. Keep person calm until medial help arrives.
  • Eye Exposure: Immediately flush eyes for at least 15 minutes with copious amounts of water until emergency personnel arrive on scene.

ALL HYDROFLUORIC ACID EXPOSURES ARE A MEDICAL EMERGENCY! IMMEDIATELY CONTACT HOSPITAL and CAMPUS SECURITY AND ARRANGE FOR IMMEDIATE MEDICAL TRANSPORT. A COPY OF THIS POLICY andSDS MUST BE TO THE MEDICAL PERSONNEL.

IV. Waste disposal procedures and accidental releases. 
Spent HF solutions is disposed of as hazardous waste through EH&S.  Drain disposal is not allowed. You must consult EH&S for disposal if you have any question.

V. Spill Management
All areas where HF is used must have proper spill control kit. Small spills can be neutralized by covering with acid neutralizer/sodium bicarbonate, and absorbed with spill control pads/absorbents. Once the spill is contained isolate the room and leave the area immediately. Call EHS for help.

If it is a large spill immediately evacuate all persons in the area and close all doors. Any type of spill/accidental release of HF must be reported immediately to EHS during working hours at MS Campus (212) 854 – 8749; at CUMC Campus (212)-305-6780, and at LDEO Facilities (845) 365-8600 and LDEO Security and Safety (854) 365-8865 after hours call the Public Safety at (212) 854-5555 and ask for EHRS.

VI. Incompatibles and Storage
Store HF in a cool and dry place away from incompatible materials separated from other chemicals. NEVER STORE HF IN GLASS CONTAINERS!  Hydrofluoric acid reacts with many materials therefore avoid contact with glass, concrete, metals, water, oxidizers, reducers, alkalis, combustibles, organics and ceramics. HF must be stored in tightly closed containers made of polyethylene or fluorocarbon plastic, lead, or platinum. Secondary containment of polyethylene must also be used.
 
Protect containers from physical damage. Storage facilities should have adequate ventilation and constructed for containment and neutralization of spills. Handling and storage of HF requires special materials and technology for containers, pipes, valves, etc., which is available from suppliers. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product.

MEDICAL SURVEILANCE:
A separate policy is attached with this document (see Attachment A) detailing complete medical surveillance and emergency response.

  • Immediately wash the contaminated area with copious amount of water then carefully apply calcium gluconate gel as per instructions of the manufacturer.
  • Take injured person to the local area Hospital for further assessment and treatment by the medical personnel. It is recommended that the person be accompanied.
  • If transport is not available an ambulance must be called; speed of treatment is of the essence.

Any Department working with HF must keep Calcium gluconate gel on-site.  It is the responsibility of the PI to maintain an up-to-date stock.  PI must inform employees about the presence and location of the gel, advise to use it and this policy before they allowed working.

DELAY IN FIRST AID OR MEDICAL TREATMENT OR IMPROPER MEDICAL TREATMENT WILL LIKELY RESULT IN GREATER DAMGE OR MAY, IN SOME CASES, RESULT IN FATAL OUTCOME.

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INFORMATION AND TRAINING

  • The Principle Investigator shall train employees who handle hydrofluoric acid on the hazards of HF and what to do in the event of an exposure or a spill or other emergency.
  • The SDS together with this policy shall be used to train employees on the hazards of HF
  • A Safety Data Sheet (SDS) on HF and copy of this policy must always be kept in the immediate work area where HF is used.

RESPONSIBILITIES

  • PI
  • Must ensure personnel are trained in the safe use of HF and this policy.
  • Ensure stocks of calcium gluconate are on hand in case of emergency.
  • Ensure HF spill kit is present and workers know how to use in case of a spill.
  • Require employees to work in a buddy system.
  • Facilities
  • Check integrity of fume hoods periodically to ensure they are working properly.
  • Ensure their employees DO NOT work on fume hoods when they are in use.
  • Ensure employees responding to repair and emergencies are familiar about HF hazards and use appropriate PPE.
  • Coordinate with PI for routine maintenance of fume hoods.
  • EH&S
  • Provide fume hood certification annually.
  • Follow up on exposure or spill incidents
  • Review and update this policy as necessary
  • Provide training

VII. ATTACHMENTS

ATTACHMENT A: Toxicological Properties of Hydrogen Fluoride
ATTACHMENT B: Policy for Handling and Treatment of Personnel Exposed to Hydrogen Fluoride
ATTACHMENT C: General information about HF and medical follow-up
ATTACHMENT D: Material Safety data Sheet (SDS) of Hydrofluoric Acid (HF)

ATTACHMENT A

Toxicological Properties of Hydrogen Fluoride

I.  Properties of hydrogen fluoride.  Hydrogen fluoride gas and hydrofluoric acid have nearly the same toxicological properties in living tissues/systems, and can be considered interchangeable; for the purposes of this section of the policy, the term “HF” will be used to denote either the gas or the liquid acid.  The use of HF gas at CU tends to be confined to the Department of Electrical Engineering, often in gaseous mixtures (5% HF) with Helium or Neon.

In aqueous solution, hydrofluoric acid is only a weak acid, having a pKa = 3 (in contrast, HCl has a pKa = -8, and perchloric acid has a pKa = -10).  In terms of acid strength (i.e., degree of dissociation in water), HF is similar to formic acid.  HF does not dissociate strongly in water because HF molecules form hydrogen bonds with water molecules and because there is a large negative change in entropy when HF molecules react with water (less entropy = more order).  Other hydrogen-halide molecules form only weak van der Waals forces with water molecules.

HF interacts corrosively with a wide variety of materials. This property makes HF both useful and hazardous.  HF dissolves most metals, natural rubber, concrete, glass, fiberglass, ceramics and glazes.  HF does not attack metallic Lead and Platinum, polyethylene, polypropylene, Teflon, Plexiglas (= acrylic), and wax.

Airborne concentrations of HF are difficult to detect precisely using direct-reading electronic instrumentation, and HF-specific test strips tend to have a large margin of error.  However, HF has good warning properties, detectable by humans at concentrations as low as 0.04 ppm (the OSHA Permissible Exposure Limit (PEL) for HF is 3 ppm)

II.  Toxicology of hydrogen fluoride.  In the body, HF readily penetrates skin, corroding soft tissue and bone.  Inhaled HF vapor/gas is corrosive to the respiratory system and can cause delayed pulmonary edema.  Systemic HF poisoning removes Ca2+ from soft tissues and bones, creating a disturbance of Ca2+ concentrations (hypocalcaemia).  Ca2+ regulation is critical for normal cell function, neural transmission, bone integrity, blood coagulation and intracellular signaling.  Sudden death following acute HF exposure is common.

Use the utmost care in preventing exposure to even the most dilute HF solutions.  Although exposure to concentrated HF solutions (>50%) will cause immediate pain, more dilute solutions (20% - 50%) may not cause any pain on contact and may go undetected for hours.  Delays in first aid/treatment of HF exposure result in painful, slow-to-heal burns and systemic HF poisoning.

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ATTACHMENT B

Columbia University
Environmental Health & Safety

Policy for Handling and Treatment of Personnel Exposed to Hydrogen Fluoride

PURPOSE       This policy ensures proper decontamination, emergency handling and treatment of personnel exposed to hydrogen fluoride (HF) at Columbia University.

APPLICABILITY:  This policy covers all Columbia University personnel at all campuses.

SCOPE   Occupational exposure to hydrogen fluoride is a true medical emergency. Personnel exposed to HF liquid solution or condensed vapors must be decontaminated with copious amount of water to avoid secondary contamination. Rescuers should don proper personal protective equipment (PPE) before coming in contact with contaminated individuals and clothing.

PROCEDURE    HF is a highly corrosive and odorous substance that can cause immediate or delayed severe injury.  Systemic effects include cardiac arrhythmia and electrolyte abnormalities, which can lead to sudden death.  Inhalation of HF vapors can cause respiratory irritation, swelling and fluid accumulation in the lungs (pulmonary edema). Symptoms may be delayed for several days, especially in case of exposure to dilute solutions of HF (less than 20%). The following procedures should be followed:

1. Decontamination

  • Rapid decontamination is critical. Contaminated clothing should be removed, double bagged and labeled as hazardous waste.
  • Exposed skin should be washed with water for 15 minutes.
  • Burned areas of the skin should be treated with topical calcium gluconate gel.
  • If eyes are affected, irrigate with water or saline solution for at least 15 minutes.

2. First Aid

  • In an emergency, attention should be given to the airway breathing and circulation of the exposed person.
  • Properly protected responders (trained and attired) should remove the exposed person from the contaminated area.
  • In case of ingestion, an exposed person who is conscious should be given 4 to 8 ounces of water or milk.  In addition, 4 ounces of an anti-acid, such as Maalox, may be given.

3. Transportation

  • After decontamination, the exposed person should be transported as soon as possible to the nearest Emergency Room.

RESPONSIBILITY

1. Supervisor

  • Provide a copy of policy and attachments to the EMS personnel.
  • Notify Environmental Health and Radiation Safety (EH&S) Department at (212) 854-8749 (MS) or 212-305-6780 (CUMC) with the workers name, location and nature of the incident, telephone contacts as well as the name and location of the medical facility the exposed person was taken to for medical treatment.
  • Notify Public Safety about the hydrogen fluoride exposure.
  • Complete the Incident Form and fax it EH&S at (212)305-0318.

2. EH&RS/EHS

  • Shall investigate the incident and make appropriate recommendations to avoid recurrence.

Created by Marc Wilkenfeld, MD and Muhammad Akram, PhD,       
Effective 7/07

ATTACHMENT C

General Information about HF and Medical Follow-up 

See Recommended Medical Treatment for Hydrofluoric Acid Exposure
(Honeywell HF Information; http://www.hfacid.com)

ATTACHMENT D

  Safety Data Sheet (SDS) of Hydrofluoric Acid
(Copy of SDS attached from J. T. Baker Chemical Company )

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