Handling and storage of chemicals in laboratory is one of high risk issue in research process that make danger to human life and safety in R&D. This article have a short review to how do it correctly. There is no single simple formula for working safely in the laboratory, since each lab facility and each experiment presents unique challenges. We will be addressing safety issues with each experiment that we do in this course and give you some specific guidelines for safety throughout the semester.

A. MSDS (Material Safety Data Sheets)

While each chemical that you use will have its own unique properties, there are some common practices that will aid you in treating them all with the level of respect that they are due. For example, labeling each chemical is required under the law and should be thorough enough so that even a person who does not work in the lab can identify any chemical. Also, every chemical in the laboratory should have a Material Safety Data Sheet (MSDS) on file and readily available. The MSDS is a legally required technical document, provided by chemical suppliers, that describes the specific properties of a chemical. Besides the MSDS on file in the lab, several web sites offer MSDS databases. They are all broken down to the same 8 sections:

1. Chemical identity. The manufacturer’s contact information is here, along with contacts for emergency

situations.

2. Hazard ingredients/identity. Some reagents have multiple components, and many single-component

chemicals have alternative names. These are all listed here. Concentration limits for airborne exposure to a chemical are listed here. Although these indices of toxicity are mainly of concern for production workers in factories, they are also useful for evaluation of short-term exposures. The TLV (threshold limit value) is the maximum airborne concentration of a substance to which workers can be repeatedly exposed without adverse effects. The units used are usually parts per million (ppm) or mg/m³.

3. Physical chemical characteristics. This list of physical properties tells you whether the chemical is solid

or liquid and how volatile it is.

4. Fire and explosion hazard data. This is of particular interest in cases where fire-fighting methods must

be selected.

5. Reactivity data. This information is essential in determining the proper handling and storage of chemicals.

By knowing the reactivity patterns of a chemical, you know what substances or conditions from which you must isolate the chemical. For example, acids and bases react with each other rapidly, giving off large amounts of heat, so should not be stored next to each other. Others react with water and should be stored in sealed containers with desiccants.

6. Health hazards. The best source of specific toxicology data is given here, such as symptoms of acute damage

from exposure and some recommended emergency procedures. If a chemical has been tested for its

carcinogenicity, or cancer-causing potential, that information is listed here. In addition, levels at which a chemical has been found to be lethal (called the LD₅₀ for lethal dose for 50% of test animals) is listed here. Since the LD₅₀ is dependent on which type of animal it was tested on, as well as how the animal was exposed to the chemical, this information always requires these specifics. For example, the lethal dose for chemicals is much lower if injected than it is if ingested. The most common index reported is the LD₅₀ for a rat in mg of chemical per kg of animal, administered orally (ingestion). For volatile chemicals, the toxicity of breathing it is measured as the LC₅₀ (lethal concentration in air for half of the test animals), measured in ppm; in all cases, the lower the number for the LD₅₀, the more toxic the chemical.

7. Precautions for safe handling and use. This describes how to deal with spills.

8. Control measures. Specific recommendations for personal protective equipment (PPE) are given here.

B. NFPA Ratings (National Fire Protection Association)

Another quick assessment of a chemical’s health hazards that is usually available on its container is a rating by the National Fire Protection Association (NFPA). A color-coded diamond shape lists numbers rating a hazard as:

Blue for health hazard Red for flammability Yellow for reactivity

0 – normal material 0 – will not burn 0 – stable

1 – slightly hazardous 1 – flash point > 200^o F 1 – unstable if heated

2 – hazardous 2 – flash point > 100^o F 2 – violent chemical change

3 – extreme danger 3 – flash point < 100^o F 3 – shock and heat may detonate

4 – deadly 4 – flash point < 73^o F 4 – may detonate

The uncolored station of the NFPA diamond is for specific hazards:

OX – oxidizer compound

ACID – acidic compound

ALK – basic compound

CORR – corrosive compound

W – use NO WATER

2. General Safety Precautions in Handling Hazardous Chemicals in the Lab

There are generally four routes to exposure to hazardous chemicals that you should keep in mind while handling them:

Inhalation – avoid by the use of fume hoods and masks

Skin & eye contact – avoid by the use of lab coats, gloves, and goggles

Ingestion – avoid eating or drinking in the lab or leaving the lab without removing gloves

and washing hands

Injection – dispose of broken glass and needles properly

Because chemicals pose so many different kinds of hazards, there are no simple rules of thumb for safe handling of them all except for some common sense measures:

• Treat all chemicals as if they were hazardous until you learn otherwise.

• Label all containers with contents, including concentrations and date that they were transferred.

• If a hazardous material is contained, label it with a warning.

• Think through your experiment BEFORE doing it, making sure that you will not be combining incompatible chemicals.

• Clean your bench top before and after use.

• Wash hands often and ALWAYS before leaving the lab.

• Take off lab coats and gloves before leaving the lab.

• Always remove gloves before touching phones, doorknobs, light switches, etc.

• Ensure proper waste disposal and labeling.

Here are some specific tips for handling the different types of hazardous chemicals:

• Flammables: Do NOT heat these reagents unnecessarily, and never in the presence of a flame or source of a spark. In general, only open containers in fume hoods. When storing more than 10 gallons of flammable liquids, a special explosion proof storage cabinet is required.

• Corrosives: Wear personal protective equipment (PPE) such as lab coats, goggles and gloves, and always add strong acids or bases to water when making solutions. Neutralize slowly to avoid rapid generation of heat and gases. Strong acids and bases should never be stored together.

• Reactive chemicals: Wear PPE such as lab coats, goggles and gloves, and know the reactive properties of the chemical. Always store oxidizing chemicals away from flammable materials.

• Toxic chemicals: Wear PPE such as lab coats, goggles and gloves, and know the toxic properties of the chemical. When working with a dry powder, wear a mask to avoid breathing the dust. Be aware of the waste disposal procedures for unused reagents and materials that come in contact with the chemical.

Here are some of the most common hazardous chemicals that you will encounter in the biotechnology lab:

Carcinogens – formaldehyde Mutagens – ethidium bromide

Neurotoxins – acrylamide Teratogens – formamide

Nephrotoxins – acetonitrile Hepatotoxins – chloroform

Corrosives – phenol, strong acids & bases

Often vendors such as Fisher Scientific have safety information in their catalog about chemicals that they sell, in which case you can easily assess chemical hazards before you order a chemical. Spectrum Chemical also has a very large collection of MSDS on their website.