This document discusses fumigation as a process to sterilize operating rooms. It describes various fumigation methods and chemicals used, such as formaldehyde and phosphine. Formaldehyde is commonly used to fumigate operating rooms by heating a formaldehyde solution to generate gas. The room is sealed for hours to allow the gas to kill microbes before ventilating. While effective, formaldehyde is a potential carcinogen. Alternative sterilization methods aim to provide sterile environments without toxic fumigation chemicals. Strict cleaning and ventilation standards combined with limiting staff traffic can sterilize operating rooms safely.

2. Fumigation
Arya S.S
CRRI

3. Introduction
 Surgical site infections (SSIs) are the second most common
cause of hospital acquired infections.
 The source of SSIs may be endogenous or exogenous, which
includes surgical personnel ,the operating room environment
(including air), and tools, instruments, and materials brought to the
sterile field during an operation.
 By maintaining sterile environment in operation theatre we can
control major part of exogenous infections.
 Fumigation is the process by which we can sterilize the
enclosed area by injecting the chemical which will kill or
destroy microbes present in the air.

4. Fumigation
 Fumigation is a process of gaseous sterilisation which is used
for killing of micro-organisms and prevention of microbial
growth in air, surface of wall or floor.
 It is generally used in the pharmaceuticals, operation
theatres, hospitals, hotels and offices and wherever required.
 Method of fumigation completely fills an area with gaseous
fumigants to suffocate or poison the microbes & pests within.

5. Widely used fumigants include:
• Formaldehyde
• phosphine
• 1,3-dichloropropene
• chloropicrin
• methyl isocyanate
• hydrogen cyanide
• sulfuryl fluoride
• Iodoform
• Methyl bromide
Fumigation equipment

6. Formaldehyde
 A gas at room temperature, formaldehyde is colorless
and has a characteristic pungent, irritating odor.
 When dissolved in water, formaldehyde forms a hydrate
methanediol.
 A saturated water solution, that contains about 40%
formaldehyde by volume or 37% by mass, is called "100%
formalin".
 A typical commercial grade formalin may contain 10– 12%
methanol added to suppress oxidation and polymerization.

7.  Formaldehyde at approximately 5% in a
solution with water is used as a fumigant and
disinfectant in hospitals.
 Formoldehyde kills microbes
 In order to be effective, the gas has to
dissolve in the film of moisture surrounding the
bacteria, for this reason relative humidities in
the order of 75% RH and temperature above
22°C.
Formaldehyde molecule

8. Methods Electric Boiler Fumigation Method: For Each 1000 cu.ft 500ml
of formaldehyde added in 1000ml of water in an electric boiler.
Switch on the boiler, leave the room and seal the door. After
45 minutes switch off the boiler without entering in to the
room.
 Potassium Permanganate Method: For every 1000 cubic feet
add 450gm of Potassium permanganate (KMnO4) to 500 ml
of formaldehyde. Take about 5 to 8 bowels with equally
divided parts of formaldehyde and add equally divided KMnO4
to each bowel. This will cause auto boiling and generate fume.

9. Neutralisation
 After the initiation of formaldehyde vapour
immediately leave the room and seal it for at least 48
hours
 Neutralise residual formalin gas with Ammonia by
exposing 250ml of Ammonia per litre of
Formaldehyde used.
 Place the Ammonia solution in the
centre of the room and leave it for
3 hours to neutralise formalin vapour.

10. Quantity Example
 Operation Theatre volume= L×W×H=20×15×10= 3000
cubicfeet
 Formaldehyde required for fumigation=500ml for 1000
cubic feet
 So 1500ml Formaldehyde required
 Ammonia Required for neutralisation=150ml of 10%
ammonia for 500ml of formaldehyde
 So 450ml of 10% ammonia required

11. Phosphine
 Phosphine is the compound with the chemical formula PH3.
 It is a colorless, flammable, toxic gas. Pure phosphine is
odorless, but technical grade samples have a highly
unpleasant odor.
 Phosphine-producing materials have become the
predominant fumigants used for the fumigation of OT.
 It is available in solid formulations of aluminum
phosphide or magnesium phosphide.

12.  When exposed to heat and moisture the formulations release
phosphine, a highly toxic gas.
 The time required for release of phosphine will vary with
temperature and formulation.
 Phosphine is very toxic to all forms of animal life, hence
exposure of human beings even to small amounts should be
avoided.
 Phosphine can be produced via tablets or phosphine
producing equipment.

13. Phosphine producingEquipment Phosphine Tablets
* Phosphine is generaly used for fumigating huge
quantity of food grain than operation theatre

14.  1,3-dichloropropene & chloropicrin
 1,3-dichloropropene & chloropicrin is generaly used as
soil fumigants only
chemical in the
Methyl isocyanate
 Methyl isocyanate is an intermediate
production of carbamate pesticides.
 Methyl isocyanate fumes can also be used as a fumigant.
 Methyl isocyanate (MIC) is extremely toxic.
 It was the principal toxin involved in the Bhopal disaster.
 Even small quantity is extremely toxic to humans, so currently
not used in fumigation.

15. Methyl Bromide
widely used fumigant for Methyl Bromide is most
quarantine purposes
 It is a preferred fumigant because of its good penetrating
ability, rapid action, high toxicity to a broad spectrum of micro
organisms and pests.
 The effectiveness of methyl bromide is based on the
following:
• Dosage of the fumigant
• Duration of exposure
• Temperature

16.  When fumigation is carried out with Methyl Bromide fumigant,
there will not be any residual issues as aeration can be
carried out easily.
 Methyl Bromide fumigation can be carried out at the dosage
that varies between 32 grams/ m3 and 80 grams/ m3 as per
the requirements.
 Methyl bromide is considered to be a significant ozone
depleting substance (ODS) by atmospheric scientists.
 Methyl bromide is readily photolyzed in the atmosphere to
release elemental bromine, which is far more destructive to
stratospheric ozone than chlorine.

17. Preparation for fumigation
 First the area intended to be fumigated is usually covered to
create a sealed environment.
 The fumigant is released into the space to be fumigated.
 The space is held for a set period while the fumigant gas
percolates through the space and acts on and kills any
infestation.
 The space is neutralised & ventilated so that the poisonous
gases are allowed to escape from the space, and render it
safe for humans to enter.

18.  Windows, doors should be closed. AC and AHU should
be switched off before starting fumigation.
 Area under fumigation, do not enter status label should be
displayed on either side of the entrance.
 Fumigants are irritating and toxic to human eye, nose
and throat. Therefore use of nose
mask and goggles while doing
fumigation is advisable.

19.  Under certain conditions formaldehyde can react with
hydrochloric acid and chlorine containing disinfectants such
as hypochlorites to form chloromethyl a potential lung
carcinogen.
 HCl and chlorine containing disinfectants must therefore
be removed from areas before fumigation.
 Check levels of residual fumigant in the room with suitable air
monitoring equipment(formaldameter or air sampling tubes).
 The procedure is best carried out overnight.

20.  After a period of not less than 12 hours the room
must be well ventilated.
 OT is usable only when the level of formaldehyde is
less than 2ppm.
Formaldemeter

21. Personal care while Fumigation
 Adequate care must be taken by wearing cap,
mask,foot cover, spectacles.
 Formaldehyde is irritant to eye & nose; and it has
been recognized as potential carcinogen.
 Immediately leave the room after
the initiation of fumigants.
 So the fumigating employee must
be provided with personal
protective equipment.

22. Advantages of Fumigation
 Fumigants are toxic to all forms of life. Therefore, it
is
possible to control all life stages of Micro organisms.
 Fumigation is often the quickest way of controlling an
infestation, saving time and money.
 Fumigants can reach where sprays, dusts, aerosols etc
cannot reach.
 Reduced residue problems in treated areas.
 Fumigants are used where standards call for "zero
Microbial tolerance" in products or living environments.

23. Disadvantages of Fumigation
¤ Generally Formaldehyde is used for OT fumigation.
 Based on the available evidence in OSHA’s record on
Formaldehyde, it determines formaldehyde as isgenotoxic,
showing properties of both a cancer initiator and promoter.
 In humans formaldehyde exposure has been associated with
cancers of the lung, nasopharynx and nasal passages.
 Symptoms of excessive exposure include respiratory irritation,
itchy eyes, runny or stuffy nose, sore throat and headache.

24. Formaldehyde allergy
 Formaldehyde allergy symptoms include
redness, burning sensation, scaling and irritation of skin.
 Eye contact can cause pain, burning sensation, blurred
vision and excessive tearing.
 Further, formaldehyde can cause difficulty breathing in
allergic individuals, particularly those with asthma or another
respiratory condition.

25. Alternative methods
 Fumigation is an age old process of sterilisation, of the
environment, may be a sick room or operation theatres.
 In spite of brief stay of patients in the operation theatre, the
environment of operation theatre plays a great role in the
onset and spread of infections.
 But every hospital should pay good attention in proper
maintenance of air conditioning plants, ventilator systems,
and to have greater control on mechanisms and personnel
involved in disinfection.

26.  Many believe that routine Microbiological monitoring is
most essential but in reality it is not practicable.
 Special air flow pattern (the air flow pattern is such that
filtered and purified air circulates and contaminated air is
removed continuously).
 There should be restriction of personnel traffic, closing of OT
doors and a good ventilation system.
 Standard cleaning, disinfection with appropriate chemical
agents, good theatre practice, discipline, can provide a
microbiologically safe environment.

27.  Fumigation is obsolete in many developed nations in
view of toxic nature of Formalin.
 Several new safe chemicals are emerging but constrains of
economy limit the use and several hours of closure of
operation theatres can be curtailed as with Fumigation.
 Aldehydes are potentially carcinogenic and it is therefore
recommended that other agents such as hydrogen peroxide,
hydrogen peroxide with silver nitrate, peracitic acid and other
chemical compounds of formaldehyde should be used in
place of the currently prevalent practice of using
formaldehyde.

28.  These agents are dispersed with the aid of a fogger-like
device inside the theatre environment.
 The contact time is about an hour and the theatre can be
used immediately after the contact time.
Fogging method