8.9 Corrosives

OSHA defines a corrosive as “a chemical that causes visible destruction of, or irreversible alterations in living tissue by chemical action at the site of contact.” Under the DOT hazard class system, corrosives are listed as hazard class 8.

Corrosive chemicals can be further subdivided as acids and bases. Corrosives can be in the liquid, solid, or gaseous state. Corrosive chemicals can have a severe effect on eyes, skin, respiratory tract, and gastrointestinal tract if an exposure occurs. Corrosive solids and their dusts can react with moisture on the skin or in the respiratory tract and result in an exposure.

Whenever working with concentrated corrosive solutions, splash goggles should be worn instead of safety glasses. Splash goggles used in conjunction with a face shield provides better protection.

Please note: that a face shield alone does not provide adequate protection. Use of rubber gloves such as butyl rubber and a rubber apron may also be required.

Corrosive chemicals should be handled in a fume hood to avoid breathing corrosive vapors and gases.

When mixing concentrated acids with water, always add acid slowly to the water (specifically, add the more concentrated acid to the dilute acid). Never add water to acid, this can result in a boiling effect and cause acid to splatter. Do not pour the acid directly into the water; it should be poured in a manner that allows it to run down the sides of the container. Never store corrosive chemicals above eye level and always use a protective bottle carrier when transporting corrosive chemicals.

Some chemicals can react with acids and liberate toxic and/or flammable vapors. When working with corrosive materials, ensure spill cleanup material is available for neutralization, such as Calcium carbonate for acids and Citric acid for bases.

Wherever acids and bases are used, an eyewash and emergency shower must be available. If any corrosive chemical gets splashed in the eyes, immediately go to an eyewash station and flush your eyes for at least 15 minutes. The importance of flushing for at least 15 minutes cannot be overstated! Once the eyewash has been activated, use your fingers to hold your eyelids open and roll your eyeballs in the stream of water so the entire eye can be flushed. After flushing for at least 15 minutes, seek medical attention immediately and complete an Injury/Illness Report.

For small splashes of corrosives to the skin, remove any contaminated gloves, lab coats, etc., and wash the affected area with soap and water for at least 15 minutes. Seek medical attention afterward, especially if symptoms persist.For large splashes of corrosives to the body, it is important to get to an emergency shower and start flushing for at least 15 minutes. Once under the shower, and after the shower has been activated, it is equally important to remove any contaminated clothing. Failure to remove contaminated clothing can result in the chemical being held against the skin and causing further chemical exposure and damage. After flushing for a minimum of 15 minutes, seek medical attention immediately and complete an Injury/Illness Report.

Please note: some chemicals, such as Hydrofluoric acid, require the use of a special antidote (such as Calcium gluconate gel) and special emergency procedures. Read the SDSs for any chemical(s) you work with to determine if a special antidote is needed if a chemical exposure occurs.

8.9.1 Hydrofluoric Acid

Hydrofluoric Acid (HF)

Hydrofluoric acid (HF) is an extremely hazardous chemical with the potential to cause severe, life-threatening injuries from relatively small exposures. HF presents both corrosive and systemic toxicity hazards, and injuries may not be immediately painful or visible. Prompt, appropriate response following an exposure is critical.

Hydrofluoric acid is an aqueous solution of hydrogen fluoride gas. Laboratory concentrations vary widely, commonly ranging up to approximately 48% HF by weight. HF is colorless, non-flammable, and has a sharp, irritating odor. Although HF is classified as a weak acid based on dissociation, it is highly corrosive and uniquely dangerous due to its ability to penetrate tissue and bind calcium and magnesium, leading to serious local and systemic effects.

HF readily penetrates skin and can cause deep tissue damage. Fluoride ions bind calcium in blood and tissues, which can disrupt normal physiological function and result in severe injury or death if not treated promptly.

Training, planning, and authorization

Because of the significant hazards associated with HF, its use requires advance planning and additional controls.

All HF users must complete EHS Hydrofluoric Acid Safety Training and receive task-specific training from their supervisor.
A laboratory-specific Standard Operating Procedure (SOP) must be developed and available for all HF work.
HF work must be reviewed and approved by the Principal Investigator before use begins.

Designated areas and engineering controls

HF must be used only in a designated chemical fume hood.
Designated HF hoods must be clearly identified using an HF designated area sign.
HF containers must be kept closed when not in use and handled over compatible secondary containment.

First aid and spill preparedness

An HF first aid kit containing 2.5% calcium gluconate gel must be readily available in areas where HF is used.
Calcium gluconate gel must be monitored for expiration and replaced as needed.
An HF spill kit containing calcium-based neutralizing agents (e.g., calcium carbonate, calcium sulfate, or calcium hydroxide) must be available.
Sodium bicarbonate must not be used for HF spills, as it does not bind fluoride ions and may generate hazardous aerosols.

Personal protective equipment (PPE)

PPE must be selected based on the specific task and HF concentration. At a minimum, HF work requires:

Acid-resistant apron and arm protection
Gloves:
- Incidental contact: double nitrile gloves, changed immediately if contaminated
- Extended handling: HF-compatible gloves (e.g., neoprene or butyl) worn over inner gloves
Splash goggles used in conjunction with a fume hood sash
Closed-toe shoes
Long pants and long-sleeved clothing

Safe work practices

Never work alone with HF; use a buddy system.
Use compatible secondary containment when handling HF.
Store HF in compatible containers within labeled secondary containment.
Store HF in lower cabinets to reduce spill risk.
Wash gloves with water before removal.
Ensure the Safety Data Sheet (SDS) for HF is readily accessible.

Additional technical and medical response information for HF exposure is available through recognized industrial and medical references. For questions about HF hazards, controls, or emergency response planning, contact EHS at askEHS@cornell.edu.

8.9.2 Perchloric Acid

Perchloric acid is a strong oxidizing acid that can react violently with organic materials. Perchloric acid can also explode if concentrated above 72%. For any work involving heated Perchloric acid (such as in Perchloric acid digestions), the work must be conducted in a special Perchloric acid fume hood with a wash down function. If heated Perchloric acid is used in a standard fume hood, the hot Perchloric acid vapors can react with the metal in the hood ductwork to form shock sensitive metallic perchlorates. When working with Perchloric acid, be sure to remove all organic materials, such as solvents, from the immediate work area. Due to the potential danger of Perchloric acid, if possible, try to use alternate techniques that do not involve the use of Perchloric acid. If you must use Perchloric acid in your experiments, only purchase the smallest size container necessary.

Because Perchloric acid is so reactive, it is important to keep it stored separate from other chemicals, particularly organic solvents, organic acids, and reducing agents. All containers of Perchloric acid should be inspected regularly for container integrity and the acid should be checked for discoloration. Discolored Perchloric acid should be discarded as hazardous waste. Perchloric acid should be used and stored away from combustible materials, and away from wooden furniture. Like all acids, but particularly with Perchloric acid, secondary containment should be used for storage.

Environment, Health and Safety