8.0 Hazard Evaluation and Process Risk Reduction Assessment

Danger:

  • HF is highly corrosive to metals, glass, skin, tissues and bones.

  • Any HF work must be performed within a chemical fume hood.


Hazards Evaluation

HF is one of the most corrosive inorganic acids. Per GHS classification of chemicals, HF is both a physical hazard (corrosive to metal, glass, enamel, etc) and a health hazard (acute poison and corrosive to skin, eyes, respiratory system, bones, etc.) as shown in the pictograms below.

  • HF is acutely toxic and extremely destructive to the body tissue and respiratory tract.
  • Exposures to HF will result in skin burns. Dermal exposure will cause sever and painful burns.
  • HF in any concentration and quantity is highly hazardous to the human body system.

 

Hydrofluoric acid
    

Below are example pictograms, hazard statements, signal words, and risk statements for different HF concentrations in water or other formulations.

GHS Pictograms

Hazards and Signals

Risk Statements

HF conc.  ≥ 3M ( ≥ 6%)

Danger

Danger - Corosive to respiratory and body systems, eye, and bones.

Ingesting ~1.5 ml of 40% HF is fatal.

Acutely toxic if inhaled, in contact skin, and if swallowed.

Causes severe burns.

 

 

pictogram
Warning  - Corrosive to respiratory and body systems eyes, bones.
(Conc. HF is typically used for stripping industrial parts made of stainless steel.

HF conc. 0.05 M to 0.5 M
(0.1 to 1%)

Danger

Danger - Corrosive to respiratory and body systems, eyes, and bones.

Toxic if inhaled, in contact with skin, and if swallowed.

Causes burns

pictogram
Warning - Corrosive to metalsCorrosive to metals
HF conc. 0.05 M to 0.5 M
(0.1 to 1%)
Danger - Corrosive to respiratory and body systems eyes and bones

Harmful if inhaled, in contact with skin, and if swallowed.

Irritant for the eye, the respiratory track and the skin.

Risk Reduction Assessment

Whenever possible, researchers should consider elimination or substitution of HF with less dangerous reagents, changing procedures to minimize the amount of HF used, or alternate processes. A basic risk assessment for various activities including risk minimization recommendations for safe handling of HF is summarized below.

HF Storage or Process Application

Recommendations For Risk Reduction

Typical Storage, Usage Quantity and Frequency of Use.

Storage or Process Risks

Storage  (concentrated acid)
  • When not in use, tightly seal the container.
  • Store HF reagent bottles in a secondary storage container within a corrosive acid cabinet.
  • Label the secondary storage container (an example of labeled secondary containers is depicted in section 7).
  • Minimize HF inventory to one or two bottles.
More than two 500 ml bottles (40% higher concentration)

HIGH

Two 500 ml HF bottles (40% or higher concentration)

MODERATE

One 500 ml HF bottle (40% or higher concentration)

LOW

Storage (concentrated acid)
  • Store HF reagents tightly capped in PE or PP containers.
  • Store diluted HF solutions (≥3 M) in a labeled secondary storage container within a corrosive acid cabinet or in a polyethylene tray within a fume hood.
  • Label all in-house prepared reagent containers and samples containing HF.
Diluted HF solutions and synthetic reagents

LOW

Aliquoting, pouring or dispensing HF to reaction vessels
  • Develop and implement written SOPs.
  • Work within a fume hood.
  • Wear a face shield, chemical splash goggles, appropriate gloves, and lab coat. Wear apron over lab coat.

Pouring or dispensing to reaction vessels per event, twice monthly.
(Typically 2 to 20 ml per reaction vessel, 10 samples per event.)

HIGH

Digestion of geologic rocks or clay materials
  • Develop and implement written SOPs.
  • Work within a fume hood.
  • WHERE APPROPRIATE,  SASH MUST BE KEPT CLOSED ALL THE WAY DOWN.
  • Wear a face shield, appropriate gloves, and lab coat.
  • Wear apron over lab coat if splash potential exists.
  • Ensure fume hood face velocity is within the working range to prevent any fugitive SiF4  and emission in to the lab environment from digestion process.
2 to 20 ml per sample and no more than 10 samples per event, twice monthly.
(Digestion is performed with sash closed and therefore risk is lower than the dynamic pouring/ dispensation activity.)

MODERATE

< 2 ml per sample and no more than 5 samples, twice monthly

LOW

Cleaning/etching of silicon wafer, metal, or glass surface
  • Develop and implement written SOPs
  • Work within a fume hood.
  • Wear a face shield, chemical splash goggles, appropriate gloves, and lab coat. Wear apron over lab coat.
  • When not in use, sash must be closed all the way down
2-10 ml per sample and no more than 10 samples, twice monthly.

HIGH

< 2 ml per sample, no more than 5 samples, twice monthly

MODERATE

Pyridinium hydrofluoride (synthetic reagent)
  • Develop and implement written SOPs.
  • Work within a fume hood.
  • Wear a face shield, appropriate gloves and lab coat.
  • When not in use, tightly seal the container and store in a dry, cool place.
<5 ml per sample per event.

MODERATE

Dilute trifluoroacetic acid (TFA) in water
  • Warning: TFA can hydrolyze to HF upon contact with moisture.
  • Wear chemical splash goggles, appropriate gloves and lab coat.
  • TFA mobile phase should be prepared within a fume hood.
Typically used as 0.1% TFA in water as HPLC mobile phase

MODERATE

Spill cleanup (HF spill outside of fume hood)
  • Danger: HF vapors are harmful to respiratory system (OSHA PEL is 3 ppm). All HF work should be performed within a fume hood.
  • For any quantity or any concentration less than 250 ml:
  • Alert everyone in the lab to evacuate until cleanup is finished.
  • Call EHS Emergency Response Coordinator with questions if needed (5-8501, business hours).
  • Wear a face shield, chemical splash goggles, appropriate gloves, and lab coat. Wear apron over lab coat.
  • Contain the spill and cleanup using supplies in the spill kit designated for HF.
  • For any quantity or any concentration greater than 250 ml:
  • Call 911. Inform dispatcher that an HF spill occurred outside of the fume hood. Wait for instructions from response team.
  • Alert everyone in the lab to evacuate until cleanup is finished.
  • During business hours, contact the EHS Emergency Response Coordinator to explain details of the spill (5-8501)
Any quantity and any concentration outside of the fume hood.

MODERATE

 TO

HIGH

Spill cleanup
(within a fume hood)
  • Wear a face shield, chemical splash goggles, appropriate gloves, and lab coat. Wear apron over lab coat. 
>500 ml

MODERATE

5 to 20 ml
(Both concentrated and dilute HF)

MODERATE

<5 ml
(Both concentrated and dilute HF)

LOW

Waste Disposal: Transport of either unused HF or diluted HF soln.
  • Concentrated HF stored in original containers will be picked-up for disposal by EHS. 
  • Diluted HF reagent and lab generated HF waste must by properly neutralized and stored in PE or PP containers for disposal by EHS.
  • HF-waste, including neutralized HF-waste, should not be stored in glass bottles.
  • See PPE section for appropriate PPE.

Concentrated HF soln:
40% or higher in orginal container.

 

Diluted Soln:
Process specific diluted HF reagents, process wastes, etc. should be stored in PE or PP container.

LOW