Safety & Precautions

Storage and Handling of Hazardous chemicals

As a large number of materials of different nature are to stored in process industries, warehouses, laboratories etc. it is highly essential that these are stored safely and properly and a high sense of good house keeping practice is to be maintained. For the purpose of safe storage, these chemicals can be classified into different groups, based on their chemical characteristics.

Incompatible Chemicals:

These are chemicals, which remain harmless if stored in isolation, but upon allowing to come into direct contact could pose severe fire explosion hazards.

Some of this type are:

  • Con. H2SO4 vs KMnO4
  • Glycerol vs KMnO4
  • Acetone, Methanol, Glycerine. vs CrO3
  • Con. HNO3 vs Alcohols, Ketones, Ethers
  • Sodium metal vs H2O
  • Sodium hydride vs H2O
  • Hydrogen peroxide vs Flammable Organic Solvents

In all the above cases instant fire will take place due to high amount of heat produced as a result of the vigorous reaction between these compounds.

Explosive Chemicals:

These are chemicals which under certain conditions of heat, pressure, shock etc. undergo rapid decomposition, evolving large volumes of gas and heat, which in turn further heats up the surrounding air to expand so rapidly that the entire process ends up in what is called explosion. e.g.

Nitrates (ammonium nitrate), Persulphates (ammonium persulphate), Peroxides (hydrogen peroxide), Permanganates (potassium permanganate), Perchlorates (ammonium / sodium / potassium), Dichromates (ammonium), Hydroxylamines and their salts, Azides (sodium azide) etc, etc.

Some of the recommendations for their storage are:

  • All chemicals falling under this category should be stored in a separate block, away from the main building.
  • Before storing these materials it should be ensured that the relevant MSDS is available.
  • Ensure that the environment conditions such as temperature, RH etc. is compatible to the stability of the product.
  • Avoid storage for prolonged periods.
  • Proper material handling equipments should be used during transportation from one location to another.
  • Rough handling, dragging of the containers, stacking at higher levels thus creating more strain on the bottom containers etc should be avoided.
  • No attempt should be made to scrap out the material with any metal object nor should it be pulverized or powdered.
  • Disposal of explosive chemicals should be done only as per the procedure laid down in the MSDS or as per the manufacturers instruction.

Oxidising Agents:

Since oxidising agents are capable of generating oxygen by way of heat, chemical decomposition or by interaction with other incompatible materials, they help fire to ravage even in the absence of atmospheric air or oxygen. Following categories of chemicals are considered to be most powerful oxidizers and these are to be handled very cautiously. e.g.

Peroxides, Persulphates, Perchlorates, Periodates, Permanganates, Bromates, Nitrates, Chromates, Dichromates, Perborates, etc.

As a general rule all flammable solvents must be stored away from oxidizing chemicals and these should never be allowed to come into contact with each other. Also it is advisable to store the oxidizing chemicals separately, having adequate ventilation and cooling arrangement since most of these chemicals are susceptible to thermal decomposition.

Flammable Chemicals:

Combustible materials can be of all the 3 types viz. solids, liquids or gases although the rate of fire propagation is different for each type, it is least in the case of solids, however it is much faster in case of liquid and still much faster in case of gases.

Some of the recommendations for storage are:

  • All flammable solvents must be placed in a cool place under shelter with proper ventilations.
  • The containers should be properly closed and should not be leaking/damaged condition.
  • No hot jobs such as welding, gas cutting, grinding or any other source of ignition such as naked flame, smoking etc should not be allowed in and around the storage area.
  • No electrical equipments and fixtures must be avoided in the storage block, if installed they should be flameproof in nature and earthing should be provided.
  • Adequate fire fighting equipments should be available at strategic locations to handle emergency.
  • Proper colour coding should be implemented for correct identification.

Water Sensitive Chemicals:

There are many chemicals which are highly reactive with water/moisture. Upon contact with water they react violently resulting in fire/chemical splash. These are to be stored in leak proof water tight containers in a dry place or dry sand beds preferably which act as good adsorbant in case of leakage. e.g. metallic elements such as sodium, potassium, rubidium, magnesium, lithium etc. metal salt such as Acetic anhydride, Calcium hydride, Sodium metal, Sodium hydride, Con. Sulphuric acid, Nitrides, sulphides, carbides, borides etc. organic chloro compounds such as Acetyl chloride, Aluminium chloride, Thionyl chloride etc. Only recommended fire fighting agents such as Dry powder, CO2 should be used in the affected area.

Toxic Chemicals:

These chemicals can be both organic or inorganic as well as in all 3 forms viz. solid, liquid or gas.

Some of the precautions recommended in their storage and handling are:

  • Store these chemicals especially if they are in liquid form in well closed containers in a cool place with adequate ventilation.
  • Ensure that they do not come into contact with atmospheric oxygen, moisture etc as many of the otherwise harmless chemicals become toxic due to chemical degradation, with air and moisture.
  • There must be proper identification tags on toxic chemicals.
  • Ensure that toxic chemicals are not stored along with other chemicals particularly with those meant for human consumption such as IP/BP grade products.
  • All safety aids such as hand gloves, nose masks, fresh air mask, goggles etc should be available handy.
  • Appropriate antidotes against each of the toxic chemicals should be made available at the site.
  • MSDS should be consulted before going to handle toxic products.

Corrosive Chemicals:

Few of the chemicals are very corrosive in nature and can cause severe blisters/deformity/loss of vision etc, if they come in contact with human body.

All personal protective equipments such as hand gloves, apron, goggles, nose mask, safety shoes should be worn when handling these chemicals. e.g.

All mineral acids (HF,HCI,HNO3,H2SO4),Certain organic acids (formic and acetic acids), Alkalies (ammonium, sodium and potassium hydroxides), Chloro compounds (acetyl chloride, Thionyl chloride, mono and tri-chloro acetic acid, aluminium chloride) etc.

Alkalis like sodium hydroxide, potassium hydroxide, liquid ammonia solution can damage the eye permanently, if there is a splash and they come into contact with eye. No alkaline material should be handled without goggles and hand gloves

Handling Emergencies

Handling of flowing Acid Accidents:

  • Remove all persons from Danger zone.
  • Wash contaminated place with soap & water.
  • Apply Calcium Gluconate to affected areas.
  • Remove affected clothing.
  • Rinse eyes only with water.
  • Inform the Doctor.

Handling Unconsciousness:

  • Vomiting should never be indused.
  • Start mouth-to-mouth respiration.

Handling Fire Accidents:

  • Carbon dioxide is most frequently installed in the Lab. It suffocates fire and leaves no residue.
  • Use fire extinguisher for glowing or smouldering fires.
  • Use sand for metal fire.

Handling Cuts and Scratches:

  • Carefully wash with clean water.
  • Swab with cotton wool and apply surgical spirit.
  • Apply dressings in a normal manner.
  • Obtain medical attention.

Handling Burns:

  • Remove contaminated clothing.
  • Flush gently chemical burns with plenty of cold water.
  • Cover heat burn loosely with a clear towels.
  • Do not pluck blister or remove clothing sticking to the burn.

Emetics:

The response of different people to the various first aid methods used to induce vomiting is by no means uniform. A simple method is that of tickling the back of the throat with two fingers or a spoon. A useful and quickly available emetic is salt water (one tablespoonful of common salt in each cupful of lukewarm water) repeated until vomiting occurs.
It is suggested, as a guide, that the following items should be kept in a clearly labelled first aid box or cupboard.

  • A Sufficient number of small sterilised unmedicated dressings for injured Fingers.
  • A sufficient number of medium sized sterilised unmedicated dressings for injured hands or feet.
  • A sufficient number of large sterilised unmedicated dressings for other injured parts.
  • A sufficient number of adhesive wound dressing of an approved type and of assorted sizes.
  • A sufficient number of triangular bandages of unbleached calico, the longest side of which should measure not less than 130 cms and each of the other sides not less than 92 cms.
  • A sufficient supply of adhesive plaster.
  • A sufficient supply of absorbent sterilised cotton wool in a container of an approval type and size.
  • A sufficient supply of approved eye ointment in a container of an approved type and size.
  • A sufficient number of sterilised eye-pads in separate sealed packets.
  • A rubber bandage or pressure bandage.
  • Safety pins.

It is suggested that in addition to the above provisions, which cater primarily for cuts and heat burns, each laboratory first aid box should contain the following:

  • Eye irrigation bottle – ½ litre capacity.
  • Tablespoon.
  • Bottle of Common Salt.
  • Bottle of Magnesium Sulphate (Epsom Salt)
  • Bottle of Milk of Magnesia (Dose: Two tablespoonsfuls)
  • Bottle of Vinegar of Acetic Acid.