Important Properties of Chlorine related to Safety
At room temperature, it is a yellow-green gas with
a sharp, burning odor. In liquid phase it is clear,
reddish colored liquid.
Under increased pressure or at temperatures below
-30 degrees F. or above the threshold quantity of
1,500 pounds Chlorine presents a potential for a catastrophic
Specific Gravity = Gas, 2.485 (air); Liquid, 1.467
0/4°C (water) (Heavier than air as gas and water
Vapor Pressure = 53.51 psi at 0°C; 112.95 psi
at 25°C - Evaporation is total no residue left
Solubility in Water =6.93 lbs/100 gals. (60°F
and 14.696 psi)- Minor solubility
Chlorine, gas or liquid, is non-explosive and non-flammable.
It is an oxidizer and is capable of supporting combustion.
Many organic chemicals react readily with chlorine,
Reactions With Water - Chlorine is only slightly soluble
in water.(0.3 to 0.7 percent)
Reactions With Metals - At ordinary temperatures dry
chlorine, gas or liquid, reacts with aluminum, arsenic,
gold, mercury, selenium,tellurium, tin, and titanium.
Carbon steel ignites near 483°F(251°C).
Reactions With Organic Compounds - Chlorine reacts
with many organic compounds. Some reactions can be
extremely violent or explosive.
It is a highly reacting helogen combining directly
nearly all elements hence isolation is the primary
requirement for safety.
(B) Exposure to human body and ill effects
Exposure to chlorine can cause immediate burning of
the eyes, nose, and throat, warning of potentially
hazardous exposure levels. Short-term exposures to
chlorine do not often result in long-term health effects.
Long-term effects are usually found in people who
have had repeated exposures to chlorine causing them
to build a tolerance to its irritant effects, making
victims unaware of the chemical's presence. Repeated
chlorine exposure irritates the lungs, leading to
coughing, mucus production, or shortness of breath
which can last for months, even years. The very young
and elderly, as well as people with known health problems
are at increased risk from chlorine exposure.
Common Routes of Chlorine Exposure
Inhalation. The most common way for chlorine to enter
the body is through the respiratory system. Chlorine
is a respiratory irritant. The gas irritates the mucus
membranes and the liquid burns the skin. As little
as 3.5 ppm can be detected as an odor, and 1000 ppm
is likely to be fatal after a few deep breaths. In
fact, chlorine was used as a war gas in 1915.Exposure
to chlorine should not exceed 0.5 ppm (8-hour time-weighted
average - 40 hour week.)
Signs and symptoms of chlorine inhalation include:
rapid, difficult breathing; bluish skin color; wheezing
and congestion; cough; nausea and dizziness; burning,
irritated throat; swelling or narrowing of the airways;
chlorine-induced pneumonia; and possible lung collapse.
Absorption through the Skin.
Chlorine can be absorbed through the skin causing
mild to severe burns. Symptoms include: pain, inflammation
or swelling, blisters, frostbite, and tissue death.
Absorption through the Eyes.
Chlorine can be absorbed through the eyes causing
various problems. Symptoms may include: burning or
discomfort, irregular blinking, redness, tearing,
involuntary closing of the eyelids, eye burns, eye
pain, and blurred vision.
Ingestion. Chlorine may cause tissue injury upon swallowing.
(C)Working safely around chlorine
Liquid chlorine comes in two types of containers:
- Cylinders with a 68 kg (150 lb.) capacity
- Ton containers with a 907 kg (2000 lb.) capacity
Cylinders and ton containers have fusible plugs designed
to melt at 71°C when containers are exposed to
extreme heat, such as fire, the plug melts, relieving
pressure and preventing the container from rupturing
Storing chlorine - Do and Don'ts
Location Requirement :
q Use signs to clearly identify all areas where chlorine
is used or stored. Only qualified personnel are permitted
to enter these areas.
q Store chlorine cylinders and containers in a cool,
dry, and relatively isolated area, protected from
weather and extreme temperatures. If storing cylinders
and containers outside, shield them from direct sunlight,
unless they are specifically designed for un shaded,
q Note: Never apply heat to pipes, containers, or
container valves unless they have been thoroughly
purged of chlorine.
q When storing chlorine containers inside, store the
containers in a well-ventilated building, away from
any heat sources, such as steam pipes.
q Store chlorine containers on the lowest working
level but not below grade.
q Do not store chlorine near busy roadways or anywhere
else where vehicles operate. Chlorine reacts with
carbon monoxide to produce phosgene, an extremely
q Store cylinders upright and secure them against
falling. Cylinders will discharge vapors when upright
and discharge liquid when upside-down.
q Store ton containers on their sides, on steel or
concrete supports. The supports should be equipped
with trunnion wheels so that, if chlorine leaks from
the bottom valve, the container can be quickly rotated
with the leak at the top to minimize leakage. Discharge
ton containers while they are horizontal, with the
two valves in a vertical line (vapour from the top
valve, liquid from the bottom).
Housekeeping in Storage place
q Do not store materials that may react violently
with chlorine in the same room as chlorine (for example,
hydrogen, ammonia, acetylene fuel gases, ether, turpentine,
and most hydrocarbons, such as solvents, greases or
oils, finely divided metals, and organic matter).
q Store containers with enough room between them to
allow for complete accessibility during an emergency.
q Use cylinders and containers on a "first-in,
q Clearly tag or mark empty cylinders and separate
them from full cylinders.
q Note: Never assume a container is empty and therefore
non-hazardous even though it may weigh empty.
chlorine - Do and Don'ts
q Handle containers with care while moving or storing
them. Do not allow containers to strike objects and
do not drop containers.
q Do not use slings or magnetic devices to move chlorine
q Use new gaskets as recommended by the chlorine supplier
each time a cylinder or container is connected.
q Follow the chlorine supplier's recommended disposal
procedures for leaking containers.
q Do not modify, alter, or repair containers and valves.
Only the supplier should carry out these tasks.
q Ensure that cylinders have valve protection hoods
in place when not connected to a system.
q Do not lift a cylinder by its valve protection hood.
The hood is not designed to carry the weight of a
q Till possible, open valves by applying a steady
force to a 200 mm (8 in.) wrench.
q If the valve is very difficult to open, loosen the
packing nut slightly. Tighten the packing nut after
the valve is opened or closed.
Repair and maintenance
q Employers are responsible for providing written
preventive maintenance procedures and written emergency
procedures to any person who works on a chlorine system.
q Workers should be familiar with these procedures
before carrying out repairs or maintenance on the
q Qualified workers must supervise the cleaning and
repairing of chlorine systems.
q The chlorine system must be shut off before cleaning
or repairing it, and all piping and other equipment
must be thoroughly purged with dry air or nitrogen.
Vacuum systems can be purged by drawing the remaining
chlorine into the process. Do not weld any part of
a chlorine system until it has been purged with dry
air or nitrogen.
q After repair or maintenance work and before using
the system, the pressurized part of the chlorine system
must be pressurized to 150 psi with dry air or nitrogen
and tested for leaks by applying soap solution to
the outside of joints. Once detectable leaks are repaired,
the system must be retested.
Chlorine reacts with moisture to form corrosive acids.
Every precaution must be taken to keep chlorine and
chlorine equipment free of moisture, including the
q Close pipes, lines, valves, and containers tightly
when not in use to keep moisture out of the system.
Moisture causes chlorine to rupture steel pipe
q Avoid contact between chlorine and any residual
material that drips from the equipment when pipes
or lines are being dismantled before repair.
q Dry pipes and lines before use by purging with dry
air (air that has a dew point of at least -40°C)
Pipes, lines, and fittings must have all cutting oils,
grease, and other foreign material removed from them
before use. Trichloroethylene or other recommended
chlorinated solvents may be used; however, take special
precautions as required. Never use hydrocarbon or
alcohol solvents for cleaning because they can react
vigorously with chlorine.
Linseed oil with graphite or white lead, Freshly mixed
glycerin and litharge
may be used as a lubricating pipe dope for threaded
joints. If Teflon tape is used, all remnants must
be removed before joints are remade.
Because iron and steel will ignite in chlorine at
about 230°C (450 - 500°F), all welding or
burning must only be done after the chlorine equipment
is completely emptied and purged with dry air or nitrogen.
Engineering controls (building design)
specific design and ventilation requirements and guidelines
for chlorine systems and storage facilities.
Consider the following points when designing a chlorine
system or storage facility:
q Containers and equipment must be located in a separate
enclosure with fire-resistant floors and walls. If
possible, chlorine containers should be housed in
a room separate from the area where the chlorination
equipment is located.
q Chlorine storage enclosures must be designed so
that chlorine containers and equipment are located
at the lowest level. Work areas should not be located
below the chlorine system.
q Storage rooms with floor areas larger than 60 square
meters (200 sq. ft.) must have two or more exit doors
which must open outwards and should not be self-locking
to ensure accessible escape routes.
q Each room or building housing chlorine containers
or equipment should have a viewing window at least
30 cm (12 in.) square or larger that will provide
a clear view of the container and distribution system.
q A suitable fan, having switch outside the room/
shed providing at least 15 air changes per hour, must
ventilate the chlorine storage room.
q Because chlorine gas is much heavier than air and
tends to collect at floor level, ventilation fan suction
must be located at or near floor level. Air inlets
must be located to provide cross-ventilation using
q In case of a chlorine leak or emergency, all factories
must have a working alarm that can be heard and seen
by workers. A continuous (24-hour) chlorine monitor
must be connected to the alarm system. The continuous
monitor checks chlorine concentrations in the air
and the alarm responds if chlorine concentrations
reach a certain pre-set level.
q All the workers and nearby public must be made acknowledge
about alarm sounding pattern and actions they are
required to take.
Several systems use detector tubes to give a direct
reading of the chlorine concentration. Workers must
be properly trained in detector tube use and maintenance.
When taking measurements to determine the extent and
severity of a leak outside the enclosure, workers
must wear appropriate respiratory protection.
Personal protective equipment
Controlling exposure requires strict attention to
chlorine exposure limits. Appropriate eye, skin, and
respiratory protection are essential. Workers must
be familiar with and understand the requirements of
their employer's written exposure control program.
Other Equipments required for Leak Control
Emergency kit : It must be having good no rusted condition,
and must have all the required components in order.
Kit should be easily available any time.
Other Equipments : Whole Body Protection Suit and
gloves, Shoes, Breathing apparatus of required types,
Helmets, Perfect eye protection spectacles, Dry sand
bags etc. are required to be readily available and
in usable condition.
When chlorine gas is in the air, safety glasses and
face shields will not protect the eyes. Workers in
an area that contains a chlorine concentration that
may irritate the eyes (for example, greater than 0.5
ppm) must wear eye protection with a tight seal around
the eyes or face to prevent chlorine gas entering
the eyes. At this concentration, eye protection will
be worn with the required respiratory protection.
Emergency response workers who are controlling a serious
chlorine leak must have access to full-body protective
Outlines of the types of respirators available to
protect workers from exposure to chlorine and the
limitations of each respirator. Respirator choices
must be based on the needs of each individual worksite
and the requirements of the employer's written safe
Full-face piece respirator with cartridges
A worker must wear a full-face piece respirator fitted
with acid gas cartridges during any hazardous work
where there is a chance of a chlorine leak. Full-face
piece respirators are also appropriate for leak control
where tests show the chlorine concentration to be
less than 10 ppm (IDLH level).
Full-face piece respirator with canister
Although cartridges are preferable, a worker may use
a full-face piece respirator fitted with an air-purifying
canister for leak control and repair or maintenance
procedures in chlorine concentrations less than 10
1. When a worker is repairing a leak, cartridges or
canisters can only be worn when the chlorine concentration
2. Canisters with an indicator window must be replaced
when the material in the window has changed color.
Canisters without an indicator window must be replaced
after each use. In either case, canisters must never
be used after the expiration date stamped on the label.
Half-face piece respirator with goggles
A worker may use a half-face piece respirator with
vapour-tight chemical goggles when working on a chlorine
system where there is a chance of a small leak. This
type of respirator is permitted only when the chlorine
concentration is below 5 ppm.
Self-Contained Breathing Apparatus (SCBA)
A worker must use an SCBA when a chlorine leak is
suspected and the airborne chlorine concentration
is unknown or is measured at more than 10 ppm. A worker
wearing an SCBA must not enter a contaminated atmosphere
until a second, qualified person is present, also
equipped with an SCBA, and ready to perform a rescue.
SCBA air cylinders should be refilled every six months
or after each use, whichever comes first.
There are two acceptable types of escape respirators:
bite-block respirators and half face piece cartridge
respirators fitted with acid gas cartridges. Bite-block
respirators must be worn with nose plugs. Escape respirators
may only be used for immediate evacuation of the contaminated
Anyone entering a chlorine room for any reason must
carry an escape respirator and keep it within arm's
reach at all times.
Situation of Chlorine concentration and Respirator
choice (for guidance)
Routine work in chlorine room - escape respirator
(If a leak occurs, the concentration will be unknown.
Exit room immediately.)
working on chlorine system - half-face piece respirator
with tight chemical goggles, or full-face piece respirator
(If a leak occurs, the concentration will be unknown.
Exit room immediately.)
up to 5 ppm o half-face piece respirator with tight
chemical goggles, or o full-face piece respirator
greater than 5 ppm up to 10 ppm full-face piece respirator
greater than 10 ppm SCBA, when leak occurs, or to
enter space (having Chlorine in atmosphere repair)
unknown ppm-- always assume to be IDLH level SCBA
Employers must establish a check system to ensure
the continued well-being of workers who are working
alone or at an isolated worksite. Where visual checks
are not possible, the check system may require a radio
or telephone. Workers who will need to use such a
system must be trained in the written procedure.
Emergency equipment includes eye wash and shower facilities,
first aid kits, and container repair kits. Workers
must have immediate access to each of these items
and must know how to use them in case of emergency.
First aid in various injuries:
Someone who has inhaled chlorine may be unconscious,
and may have difficulty breathing or may have stopped
breathing completely. Assess the victim's breathing:
£ If breathing has stopped, begin artificial
respiration and continue until the victim resumes
breathing. Pocket masks are recommended for artificial
respiration, although the mouth-to-mouth method may
also be used.
£ If the victim is having difficulty breathing
(for example, gasping or coughing), place the victim
in the most comfortable position, usually semi-sitting.
£ If an oxygen therapy unit and trained personnel
are available, administer oxygen at a 10-litre flow.
£ Ensure that the victim is transported to hospital
in case the victim suffers a delayed reaction in the
form of pulmonary edema. Any physical exertion, excitement,
or apprehension increases the chance and severity
of a delayed reaction. Keep the victim warm and completely
at rest. Reassure the victim while waiting for assistance
and transportation to hospital.
As soon as they resume breathing, always place unconscious
patients in the drainage position (on their side,
so fluids can drain from the mouth and airways). Never
give an unconscious patient anything by mouth.
Skin contact with chlorine can result in severe burns.
Before attempting to flush a victim's contaminated
skin, make sure the victim is breathing properly.
Follow these steps: Assess the victim's breathing
and follow the procedure as indicated for inhalation.
q As soon as the victim resumes breathing, flush the
victim's contaminated skin and clothing with large
amounts of water for 30 minutes.
q Remove all contaminated clothing while flushing.
q Continue flushing until all traces of chlorine have
q Dress obvious burns with sterile gauze and bandage
them loosely. Apply insulated cold packs to help reduce
q Get the victim to hospital.
Eye contact with chlorine (liquid or gas) for even
a short period can cause permanent disability. Flushing
must begin within 10 seconds. Follow these steps:
1. Flush the eyes immediately with large amounts of
running water (preferably lukewarm) for 30 minutes.
Hold the eyelids forcibly apart to ensure full flushing
of the eyes and eyelids.
2. After flushing has removed all traces of chlorine,
cover both eyes with moistened sterile gauze pads
and bandage, enough to keep light out.
3. Apply insulated cold packs to help reduce pain.
4. Get the victim to hospital.
Notes:1. Do not attempt to neutralize the chlorine
with other chemicals. 2. Do not apply oils, ointments,
or medications to the eyes.
What to Do When a Person is Exposed to Chlorine -
q Remove the exposed person(s) to fresh air.
q Call immediately company safety personnel.
q If the victim is not breathing, begin artificial
respiration. If the victim is breathing, place in
a seated position or lying down with the head and
upper body in an upright position. Encourage slow,
deep, regular breaths. Have a health professional
q Keep the person warm and quiet.
q Persons with serious symptoms may need to be hospitalized.
Decontamination Procedures -
q Remove soaked clothing from the victim and double-bag
q Flush exposed skin/hair with water for 2-3 minutes;
wash twice with mild soap and rinse thoroughly with
q Flush exposed or irritated eyes with water/saline
for 15-30 minutes. If the person is wearing contact
lenses, try to remove them.
What to Do in Case of an Emergency Chlorine Release
q Follow the procedures laid down in On Site Emergency
q All persons not engaged in stopping the leak should
leave the affected area until normal operating conditions
are restored. If the amount of chlorine released is
excessive, then special steps should be taken to warn
all persons in the path of the fumes.
q Small leaks may be readily located by the use of
a squeeze bottle containing ammonia water near the
suspected leak (avoid squeezing liquid on the leak).
If the container or equipment is leaking, then dense
white fumes of ammonium chloride will indicate the
exact location of the leak. Approach the leak from
the upwind side and since chlorine gas is heavier
than air, keep the head above the leak.
q If the leak is in the chlorinating or unloading
equipment, the nearest control valve between the chlorine
container and the leak should be immediately closed
and the chlorine lines emptied to the process. Leaks
around a container valve stem can generally be stopped
by tightening the packing nut.
q Use emergency kit to stop the leak but only by persons
wearing foolproof PPE
q Far as possible use the Chlorine in process using
secondary valve of the kit.
q If leakage is not controllable by kit use FRP HOOD
and scrub the Chlorine using neutralizing arrangements.
Water should never be applied around a chlorine leak
or onto a spill of liquid chlorine..
Apart from the corrosive action caused by the addition
of water, the heat supplied by even cold water may
cause the liquid in the container or on the ground
to vaporize faster. Since the pressure within a container
governs the rate of discharge, a leak can be reduced
by drawing off gaseous chlorine to the process as
rapidly as possible. If the consuming process cannot
take the gas rapidly enough, then the chlorine may
be absorbed in a solution of sodium hydroxide, soda
ash or hydrated lime.
q Notify trained personnel immediately, such as the
company's safety team and the local fire department.
Untrained persons or those without proper personal
protective equipment must not enter areas with high
concentrations of chlorine.
q Evacuate people from the hazardous area for at least
500 feet in all directions and have them stay upwind
of the chlorine release. They should be sheltered
in a building with doors and windows shut and air
conditioners turned off.
q Stop/control the source of exposure. If the exposure
is from a leaking cylinder, take it outdoors or to
an open area until completely drained and contents
q Ventilate potentially explosive atmospheres by opening
q Keep combustibles such as wood, paper, and oil,
away from the leak.
q Remove all sources of heat and ignition.
q Refer to Material Safety Data Sheet (MSDS) for more
Suggestions Based On Experience During Inspections
Accidents in factories using Chlorine are found to
be, because of the following reasons which are avoidable
by sincere efforts.
a. Improper storage place and nonscientific unsafe
pattern of storage.
b. Insufficient and poorly maintained plant, workplace
and equipments including PPE.
c. Not using standard materials like pipes, clamps,
d. Insufficient work force hence Chlorine related
processes poorly supervised.
e. Untrained or partially trained workers ( many times
ever changing contract workers) engaged in the process.
f. No sincerity towards rehearsal of On Site Emergency
Plan and Emergency Control Procedures.
g. Implementation of safety laws as a legal must,
just for protection against authorities. Hence continuity
in implementation not maintained.
h. An attitude to save money against safety compliance.
i. A wrong confidence and belief - No accident took
place in past so factory is safe.
j. Poor understanding regarding benefits of implementation
of safety laws.
k. Willful ignorance and violation of safety laws.
a. Have a positive attitude for safety, time has changed
you must change accordingly for your own at least.
b. Spend sufficient to implementing on safety related
requirements- it will prove to be your wise investment.
c. Never allow hazardous work in absence of insufficient
trained staff or with untrained work force.
d. Have best of safety equipments and maintain it
too, arrange for it's regular and random supervision.
e. Share your experiences and difficulties with near
by Chlorine user factory managements. If possible
form a Chlorine users club for local area pocket or
f. Introduce some incentive scheme for motivation
of safety related activities and attitude of employees.