Safe Handling of Acids and Bases

Introduction

Due to the potential dangers of some acids and bases, it is very important to follow certain guidelines when working with these materials. There are several steps that can be taken to help ensure that you are promoting a safe work environment for you and your employees. Following specific lab procedures, wearing the correct personal protective equipment (PPE) and using proper storage and disposal methods are all essential to accomplishing this goal.

Good Lab Practice

Here are several key tips to practicing safety in the laboratory:

1. Never work in the lab alone.
2. Do not eat, drink or smoke in the lab.
3. Never mouth pipette. Use the actual mechanical devices.
4. Make sure that all Bunsen burners are off before you leave the lab.
5. Wear correct personal protective equipment (PPE).
6. Always use secondary containment if transporting the acids or bases.
7. Keep the lab clean at all times.
8. Make sure bottles are tightly capped unless they are being heated.
9. If you are using hazardous chemicals, make sure your work is always done inside a laboratory hood.
10. Be aware of the location of spill response equipment.

Personal Protective Equipment

It is very important to wear correct personal protective equipment (PPE) for your application. Using correct eyewear, face shields, gloves, respiratory protection and chemical-resistant clothing should always be considered when working with acids and bases.

Eyewear

If you are dealing with a potential for splash, safety glasses are not sufficient; you need to wear an indirectly vented goggle for splash protection. There are three different types of protective goggles: direct vent, indirect vent and non-vented.

Direct Vent

This type of goggle offers protection from impact only. It allows air to flow in so that fogging does not occur as easily. This is NOT a good option for splash protection for that reason. It is possible when handling that an acid or base splash may come in contact with the eye through the vents. It is better to go with an indirect or non-vented goggle when handling acids and bases.

Indirect Vent

This goggle is used for protection against chemical splash. They are capped so that air can move freely in and out of the goggle but chemical splash and particles cannot. Because there is not as much space for the air to move, you may want to select a goggle that has an anti-fog coating. Indirect vented goggles do not offer protection from fumes or vapors. If you are exposed to fumes or vapors, you must use a non-vented goggle.

Non-Vented

Non-vented goggles have no holes for air flow. They are used in situations where splash and/or fumes and vapors are present. These goggles often have an anti-fog coating so that they will not fog up while in use.

Face Shields

Eyewear alone will not provide adequate protection from splashes to the face. Face shields protect not only the eye area from chemical splash, but also the rest of the face. Face shields are considered secondary protection and must be worn with safety glasses or goggles, as stated in ANSI Z87.1-2011.

Hand Protection

When working with acids and bases it is very important to wear hand protection (gloves) that is compatible with the chemicals you are using. If the glove material is not appropriate for the acid or base, you may have problems with breakthrough or degradation of the glove material. Sometimes your MSDS will tell you exactly which type of glove material is compatible with the chemical. If it does not, it is very important to do the necessary research to determine which material will be compatible. This may require contacting the business which you purchased the gloves from or visiting the Web site of the manufacturer of the glove (most of them have chemical compatibility guides available on their Web sites).

To speak directly to a Technical Service Representative regarding glove chemical compatibility, contact our Technical Service department at 1-800-356-2501.

Respiratory Protection

The four most common types of respirators used in applications where acids and bases are present are: air-purifying, powered air-purifying, supplied air, and SCBA (Self Contained Breathing Apparatus). The respirator that you choose should be acceptable for the acid or base that you are using and have a NIOSH approval.

Air-purifying respirators can be either full-face or half masks with mechanical or chemical cartridges to filter dusts, mists, fumes, vapors or gases. They are available in three types: disposable, reusable and disposable/reusable.

Disposable air-purifying respirators are intended to be used once or until the cartridge expires. The cartridges are permanently attached and have no replacement parts.

Reusable air-purifying respirators use both replaceable cartridges and parts. NOTE: The replaceable cartridges and parts must be from the same manufacturer to retain a NIOSH approval.

Disposable/reusable air-purifying respirators have few or no replacement parts except cartridges. When using air-purifying respirators, it is necessary to use cartridges that are going to be compatible with the acid or base you are working with. These cartridge types include:

Organic Vapors: Organic vapor cartridges are black in color and protect against organic vapors (compounds with carbon in them).**

Acid Gas: Acid gas cartridges are white in color and protect against chlorine, chlorine dioxide, hydrogen chloride and sulfur dioxide.**

P100: P100 cartridges are purple in color and it filters out particulates and aerosols (.3 microns in size or larger) at a 99.97% efficiency rate.

** A chemical cartridge respirator may only be used for exposure levels not exceeding (10X) the OEL (Occupational Exposure limit) as established in 29 CFR 191.134 (d)(3)(iii) (B)(2). If the exposure level exceeds the OEL, then a supplied air respirator must be used.

Powered air-purifying respirators use a blower to pass the contaminated air through a filter. The purified air is then delivered into a mask or hood. They filter dusts, mists, fumes, vapors and gases, just like ordinary air-purifying respirators. Powered air-purifying respirators would need to be used if the person has facial hair. Having facial hair can affect the fit of an air-purifying negative air respirator and that is why a powered air-purifying respirator would be selected.

Air-purifying respirators cannot be used in oxygen-deficient atmospheres or others deemed IDLH (Immediately Dangerous to Life and Health), which can result when another gas displaces the oxygen or consumption of oxygen by a chemical reaction. Oxygen levels below 19.5% are considered to be oxygen deficient and require a source of supplied air such as an airline respirator with escape bottle or SCBA (CFR 1910.134(d)(2)(i)(a) and 1910.134(d)(2)(i)(b).

Supplied-air respirators provide the highest level of protection against highly toxic and unknown materials. Supplied air refers to self-contained breathing apparatuses (SCBAs) and air-line respirators. SCBAs have a limited air supply that is carried by the user, allowing for good mobility and fewer restrictions than air-line respirators.

Air-line respirators have an air hose that is connected to a fresh air supply from a central source. The source can be from a compressed air cylinder or air compressor that provides at least Grade D breathing air.

Emergency Escape Breathing Apparatuses (EEBAs) provide oxygen for 5, 10 or 15 minutes depending on the unit. These are for emergency situations in which a worker must escape from environments immediately dangerous to life or health (IDLH).

Chemical-Resistant Clothing

Depending on the concentration of the acid and base that you are using, chemical-resistant clothing may be required. A standard lab coat may not provide enough protection for you. If concentration levels are high enough, you may even need to wear a suit that is fully encapsulated. Check your MSDS to see if there is a specific type of protective clothing required for your acid or base. If that information is not on the MSDS, try contacting the manufacturer of the chemical or the place where you purchased the acid or base.

Storage of Acids and Bases

There are several factors that should be taken into consideration when storing acids and bases. First and most important, is to make sure that acids and bases are not stored together. If there were to be a spill, chemical reactions could occur if they are stored in the same storage area. Second, make sure you check the MSDS of the acid or base to determine you are not storing incompatible chemicals together.

Also, be aware that all containers are properly labeled so that identification can be achieved as easy as possible. You should be paying close attention to expiration dates, making sure that the acid or base is disposed of on or before the expiration date. Acids and bases should be stored in an acid/base cabinet. The following is a list of some of the most common acids and bases and their specific incompatibilities. As a rule you should not be storing these acids or bases with each other.

Disposal of Acids and Bases

When disposing of acids and bases it is best to contact your local solid waste official for information on proper disposal procedures.

Sources for More Information

29 CFR 1910.1450, Occupational Exposure to Hazardous Chemicals in Laboratories

Prudent Practices for Handling Hazardous Chemicals in Laboratories,
National Academy Press, Washington D.C.
1981 ISBN 0-309-03128-1

29 CFR 1910.134, Respiratory Protection

29 CFR 1910.1000, Air Contaminants Standard (rev. 6/2011)