Use of Hazardous Chemicals

Flammable solvents

e.g. acetone, ethyl acetate, ethanol, hexane, etc.

1. Flammable solvents that are not in active use must be stored in safe containers inside cabinets designed for flammables.
2. Minimise the amount of flammable liquids stored in the lab.
3. Use flammables only in areas free of ignition sources.
4. Never heat flammables with an open flame.
5. Never store flammable chemicals in a standard household fridge.
6. Always use a fume hood while working with flammable liquids.

Oxidizers

e.g. Peroxides, nitrates, nitrites, perchlorates, chlorates, chlorites, hypochlorites, dichlorates.

1. Store oxidizers away from flammables, organic compounds and combustible materials.
2. Strong oxidizing agents like chromic acid should be stored in glass or other inert containers, preferably unbreakable. Corks and rubber stoppers should not be used.
3. Reaction vessels containing appreciable amount of oxidizing materials should never be heated in oil baths but rather on a heating mantle or sand bath.
4. Do not attempt to heat perchloric acid if you do not have access to a fume hood designed for perchloric acid.
5. Do not allow perchloric acid to come in contact with strong dehydrating agents e.g. sulphuric acid.
6. Do not order or use anhydrous perchloric acid. It is unstable at room temperature and can decompose spontaneously with a severe explosion.

Corrosives

e.g. Sulphuric acid, chromic acid, stannic acid, hydrofluoric acid, ammonium hydroxide

1. Always store acids separately from bases and flammables. Many acids are also strong oxidizers.
2. Add acid to water but never water to acid.
3. Never store corrosives above eye level.
4. Store corrosives in a tray or bucket to contain any leakages
5. Store corrosives in a wooden cabinet or one that has a corrosion-resistant lining.
6. Nitric acid should be stored in a separate cabinet or compartment.
7. Only personnel fully trained in the hazards of hydrofluoric acid should use it. Inhalation of anhydrous hydrogen fluoride can be fatal. Initial skin contact with HF may not produce any symptoms.
8. Always use HF in a properly functioning fume hood.

Reactives

Water-reactives: sodium, lithium, potassium, magnesium, zinc, aluminium, silanes, alkylaluminiums

Pyrophorics: diethylzinc, triethylaluminium, metal hydrides

Peroxide-forming: Diisopropyl ether, sodium amide, dioxane, tetrahydrofuran, butadiene, acrylonitrile, divinylacetylene, potassium amide, diethyl ether, vinyl ethers, vinylpyridine,

Shock-sensitive materials: chemicals containing nitro groups, fulminates, hydrogen peroxide (30% +), ammonium perchlorate, dry benzoyl peroxide, compounds containing the following functional groups: acetylide, azide, diazo, halamine, nitroso and ozonide.

1. Minimise the amount of reactives used in the experiment.
2. Always substitute a less hazardous chemical whenever possible.
3. Store water-reactive material in an isolated part of the lab away from any water sources.
4. Store pyrophorics in an isolated part of the lab and in a clearly marked cabinet.
5. Do not open any chemical containers if peroxide formation is suspected. The act of opening the container could be sufficient to cause an explosion. Visually inspect for crystals and unusual viscosity before opening.
6. Date all peroxide-forming material with the date received and expected shelf life.
7. Chemicals like diisopropyl ether, divinyl acetylene, sodium amide and vinylidene chloride should be discarded after three months
8. Chemicals such as dioxane, diethyl ether and tetrahydrofuran should be discarded after one year.
9. Store all peroxide-forming material away from heat, sunlight and sources of ignition
10. Never store peroxide-forming material in clear glass bottles where they can be exposed to light
11. Secure the lids and caps of the containers to discourage the evaporation and concentration of these chemicals
12. Never store peroxide-forming material in glass containers with screw cap lids or glass stoppers - friction and grinding must be avoided.
13. Never distill an ether unless it is known to be free of peroxides.
14. Store shock sensitive materials separately from other chemicals and in a clearly marked cabinet.