How to Neutralize Hydrofluoric Acid (and Why You Can't Use Sulfuric Acid Neutralizers)

Hydrogen fluoride (HF) — hydrofluoric acid — is commonly used to manufacture plastics, electrical compounds, refrigerants, and a wide range of other products.

In its pure form, it’s a clear, colorless, and corrosive liquid, and it can be extremely hazardous to workers: The Occupational Safety and Health Administration (OSHA) limits permissible HF exposure to 3 parts per million (ppm) averaged over an 8-hour work shift.

Direct contact with HF can cause severe burns, which may not present symptoms for several hours. Needless to say, any facility that works with hydrofluoric acid must maintain adequate spill response materials — and ensure that those supplies are appropriate for HF cleanup.

Why Acid Neutralizers May Not Work for Hydrofluoric Acid Spills

Standard “universal" spill kits should not be used to clean HF spills. Many acid neutralizing kits use potassium or sodium hydroxide. Combining these chemicals with HF may release gaseous HF.

Additionally, universal sorbents may contain silicon, which combines with HF to produce silicon tetrafluoride.  This is an odorless, toxic gas — in a confined space, silicon tetrafluoride exposure can occur quickly, causing severe irritation of the skin, eyes, and lungs. Silicon tetrafluoride is also an explosion hazard.

When selecting supplies, make sure that you’ve got an appropriate product to mitigate the hazard. Small hydrofluoric acid spills can be neutralized with dry sodium bicarbonate. 

Here’s the basic process for HF acid cleanup:

1. Because of the toxicity of hydrofluoric acid, you should never work alone when addressing HF spills.
2. Evacuate the area where the spill occurred. Only essential personnel (such as the spill response team) should have access.
3. Wear appropriate personal protective equipment (PPE). PPE must include safety glasses, gloves, and a chemical apron. Prior to the spill, the cleanup crew must receive appropriate spill response training, which should include instructions for donning, doffing, and removing PPE.
4. Cover the spill with dry sodium bicarbonate or a dedicated sorbent.
5. Allow sufficient time for neutralization. If using a color-changing sorbent, wait for the indicator before proceeding with cleanup.
6. Sweep up the neutralized spill with a broom and dustpan, then dispose appropriately.

After neutralization, HF is no longer hazardous, but the best practice is to treat it as a hazard. Avoid direct contact with the neutralized materials. Dispose of the waste in a landfill, following any relevant local or state regulations.

Choosing Hydrofluoric Acid Spill Response Supplies

If you’re working with HF regularly, dedicated spill kits are essential. By including the other necessary spill response supplies, spill kits minimize the time to neutralization — and limits exposure for workers.

Hydrofluoric Acid Spill Kit

Solus Group carries Hydrofluoric Acid Spill Kit, which includes a color-changing compound that indicates when HF has been safely neutralized.

The kit also includes latex overboots, silver shield gloves, a chemical apron, safety glasses, a dustpan and brush set, and bright yellow disposal bags — everything needed for an efficient spill response. 

HF Acid Spill Response: A Quick Checklist

If you’re working with hazardous chemicals, you have a responsibility to protect your workers. Here’s a quick checklist to make sure that you’re on the right track.

• Spill response teams have received training for donning, doffing, and removing PPE.
• My facility has eye wash stations and other emergency supplies near areas where HF is present.
• HF sorbents are appropriate for the hazard and do not contain silicon, sodium hydroxide, or other chemicals that may interact dangerously with HF.
• The facility has adequate ventilation. All containers with hazardous substances are properly labeled, and workers have access to SDS sheets.
• My operation has a process for replenishing spill response supplies.
• All spill response supplies are kept in consistent, highly visible locations.

Solus Group carries a variety of spill response supplies to help you build a safer, more productive facility. To find the right products for your facility, call (314) 696-0200 to connect with our sales team.