HF safety

Working with HF

Hydrofluoric acid (HF) is a highly hazardous chemical with unique properties that require strict safety protocols. This guide outlines the procedures for safe handling, spill response, and emergency actions when working with HF in the cleanroom.

Warning HF can cause severe burns, tissue damage, and systemic toxicity. Always follow these guidelines.

Chemical and Toxicological Properties

Toxicological Properties

• Fluoride ions cause soft tissue and bone damage by binding to calcium. Fluoride ions are both acutely and chronically toxic. Acute effects of HF exposure include extreme respiratory irritation, immediate and severe eye damage and pulmonary edema.
• Exposure Routes: Skin contact with HF is probably the most common route of exposure for laboratory personnel, although HF can also cause damage through eye contact, inhalation, or ingestion.
• Symptoms: May be delayed (up to 24 hours for dilute solutions).
• Fatality Risk: Concentrated HF burns can be fatal even with small exposure (2% body surface area).
• If you are exposed to hydrofluoric acid, seek medical attention immediately, even if you do not feel pain.

Operational Restrictions

No HF work outside working hours Allowed hours: Monday to Friday, 8:00–18:00 (no weekends, no holidays). A cleanroom staff member must be available in the building during HF use. HF buddy requirement: An HF buddy must be present with the user at all times. Maximum concentration: Training covers working with concentrations up to 10% HF.

Emergency Equipment

Equipment	Location
Calcium Gluconate Gel	Next to the fumehood & 2nd floor corridor emergency shower
Emergency Shower	2nd floor corridor
Large/Medium Spill Kits	Outside CR1
Sodium Bicarbonate Powder	In CR1

Additional Notes

• User Comfort: Users may stop work at any time if they feel uncomfortable.
• CR Staff Support: CR staff are available to assist or take over in case of uncertainty or emergencies.
• Training: All users must be trained in HF handling and emergency procedures before working with HF.

General Setup and Preparation

Before Starting

1. Announce the start of HF work: “I am going to work with HF.”
2. Flip the door sign to indicate HF work is in progress.
3. Find a buddy: Never work alone.
4. Check:
   1. Waste container and HF supply.
   2. Availability of calcium gluconate gel and spill kit.
5. Gown up:

1. Regular cleanroom attire (hairnet, goggles, gown, clogs, nitrile gloves).
2. Apron.
3. Barrier gloves.
4. Face shield: Optional.
5. Sleeves: Optional.

Note: Always check gloves for tears prior to use.

The responsibilities of the buddy are:

1. Hand out wipes, pipettes, and other equipment.
2. Open cabinets and assist with optical inspection.
3. Ensure the process runs smoothly.
4. Support the user in case of a spill.
5. Call for help in case of an emergency.

All authorised cleanroom users are eligible to be HF buddies but they cannot conduct any HF work unless they have received the HF handling training.

Tools and Materials

• Tweezers: Users should use their own.
• Beakers:
  • Polypropylene (PP) beakers: Available at the laminar flow bench.
  • PTFE (Teflon) beakers: Purchased and used from your own group (not public).

Workstation Setup

• Always carry out work in the dedicated HF tray
• Use 1 beaker for HF and 2 beakers for MQ water
• Do not use wipes inside the tray
• Label the beakers by writing directly on the tray with a permanent marker (use IPA to erase it later)
• Place cleanroom wipes between the HF tray and the bench airfoil, to prevent any spill outside of the tray from dripping outside the bench.

Recommended Setup Inside the Fume Hood

Standard Operating Procedure

1. Pour MQ water in the dedicated beakers
2. Announce in the room that you start handling HF (“Now I take HF from the cabinet”)
3. Pour HF in the beaker
4. Check that your gloves are dry (no liquid droplets)
   1. You should always assume that in case you see a droplet in your glove, it is HF and you should follow the procedure described later on Spill Protocols
5. Return the HF bottle in the cabinet
6. Run your process
7. Once done, place the HF waste bottle inside the sink of the fumehood. You can use the funnel to dispose the liquids
8. Pour the HF in the waste
9. Pour the first MQ in the HF beaker and then dispose it in the waste
10. Pour the second MQ in the HF beaker and then dispose it in the waste
11. Check that your gloves are dry (no liquid droplets)
12. Throw the beakers in the trash
13. Return the HF waste bottle in the cabinet
14. Announce the HF work is done (“I am done with HF”)
15. Clean up the workspace
16. Remove your barrier gloves inside the fumehood and dispose them in the chemical waste bin
17. Remove the additional safety attire

Waste Disposal and Potential Contaminiation

To ensure safety, users are requested to regularly check their safety equipment for potential sources of contamination.

• HF Waste: Dispose in the designated HF waste container below the fume hood.

Never exceed the fill line. New waste containers are found below the sink under the drying rack.

• Contaminated Materials: Gloves, wipes, or aprons exposed to HF must be treated as chemical waste.
• Once the user starts handling HF, they should not touch things outside of the fumehood (waste drawer, chemical cabinet, laminar flow fumehood, microscope).

Instead, the buddy can assist with opening drawers etc. The only exception is the N₂ gun:

The HF user is expected to handle the N₂ gun. At the end of the HF session please wipe the gun with a CR wipe and ensure that it is dry.

Spill Protocols

Identifying Suspicious Droplets

If you see a liquid drop on	Action Plan
Stainless steel airfoil	Assume it is HF. Wipe once with a CR wipe. Wipe again with a water-soaked CR wipe and let it evaporate.
Barrier gloves	Assume it is HF. Rinse gloves. Remove them by turning inside out (no wiping needed). Use a clean set of barrier gloves.
Apron	Remove the apron and leave it inside the fume hood. Evacuate the area. CR staff flushes and disposes of the apron.

Spill Inside the HF Tray

The HF work stops until the spill is removed.

• Buddy checks in with the user and contacts a CR staff member.
• User may proceed with removing the spill only if comfortable; otherwise, contact CR staff to take over.
• Dispose of the contents of all beakers.
• The spilled HF inside the tray can be disposed of either with a pipette or by tilting the tray and pouring directly into the HF waste container.
• Do not use wipes.
• Carefully rinse the tray with water to dilute any HF residues.
• Dispose of the water in the HF waste container.
• Carefully rinse the tray with plenty of water inside the sink.
• Dry the tray with a cleanroom wipe.
• User disposes of their barrier gloves.

It is recommended for the user to take a break and continue their work fresh later or another day

Spill Outside the HF Tray

Spill Location	User Actions
Outside the HF tray but inside the bench	Do not take any action—leave the setup immediately. Buddy helps remove contaminated PPE (keep PPE within the fume hood). Buddy calls for help (if user is HF-free).
Outside the HF tray and outside the bench	Do not take any action—evacuate CR1 immediately. Remove contaminated PPE outside CR1 door (in the hallway). Buddy calls for help (if user is HF-free).

Splash on the User’s Body

In case of a splash on the user’s body, the user should immediately evacuate and use the shower in the corridor of the 2nd floor.

The user and their buddy should follow the action plan bellow

Emergency Showers in the Hallway of the Second Floor

HF User:

1. Exit CR1.
2. Remove contaminated clothes in the corridor.
3. Exit the cleanroom area through the emergency door right across from CR1.
4. Start using the shower in the corridor.
5. Apply running water on the area of contact for at least 20 minutes.
6. Apply calcium gluconate gel to the affected area after 20 minutes of rinsing.

HF Buddy:

1. Keep a distance from the user.
2. Assist user with escape route.
3. Call for help.
4. Support HF user while help is on the way.

Exposure Response

Although HF exposures can result in injury, quick response will minimize the damage. All exposures should be treated immediately even though burns may not be felt for hours. HF first aid (calcium gluconate gel) and spill response kits are located in the cleanroom and users are obliged to familiarize themselves with the location and proper use of them. Affected personnel must receive medical attention for all exposures, i.e. any exposure to HF must be medically evaluated. Take a copy of these procedures and the MSDS with you to the emergency room.

Skin Contact

• Immediately wash all affected areas with water.
• Remove any clothing or jewelry that could trap or retain HF (remove goggles last).
• Flush skin for 15 minutes or until medical attention is available.
• Get medical attention.
• Apply calcium gluconate gel to the affected area (use rubber gloves) every 15 minutes and repeat flushing in between.

Eye Contact

• Immediately flush eyes for at least 15 minutes with water while holding eyelids open.
• Remove contact lenses if applicable.
• Get medical attention.
• Flushing can be limited to 5 minutes if medical personnel are immediately available to administer sterile calcium gluconate (1%) solution (via continuous drip into eyes).

Inhalation

• Move to fresh air as soon as possible.
• Get medical attention.
• Medical personnel can administer pure oxygen and calcium gluconate (via nebulizer).

The threshold limit value (TLV) for HF is 2 PPM.

First aid

Apply the four principles of first aid:

• Stop the accident
• Preserve life
• Summon assistance
• Provide first aid

If you call the emergency services via 112 you must send a colleague down to the main entrance of the HCØ building to help the paramedics locate the site of the accident.

The local emergency ward is the Bispebjerg Skadestue, 23 Bispebjergbakke, 2400 Copenhagen NV

All accidents must be reported to one of the permanent NBI staff members.

Location of emergency equipment

• Emergency showers are located in the hallway niches on all floors at HCØ except the basement. The shower head is in the ceiling and tap handle is in the wooden panel above the cabinets.
• There are showers in both cleanrooms
• Eyewash bottles are in the cleanroom and in all labs where chemicals are used
• There is a plumbed-in eyewash shower in the common cleanroom corridor
• Larger first aid kits are located in the hallway niches closest to the elevator on the 2^nd floor and 4^th floor
• Defibrillators are located in the HCØ hallway ground floor.