July1 , 2022

Formaldehyde as an ideal disinfectant in a poultry farm vis-à-vis human health concerns and safety



Formaldehyde as an ideal disinfectant in a poultry farm vis-à-vis human health concerns and safety

Formaldehyde is produced in minute quantities naturally as a result of metabolism of amino acids within vertebrate animals, including humans and chickens. Formaldehyde is also used as a preservative in some food items and in many household products, such as cosmetics, medicines and antiseptics. Formaldehyde is readily soluble in water and is commonly distributed as a 37% solution in water. It is used as an aqueous solution usually containing formalin, as a free gas, or in solid form as pellets.


Formalin is a colorless liquid, with a pungent and irritating odor, that contains 37-50% formaldehyde by mass, 10-15% methanol and 53% water. To increase its effectiveness, in larger facilities, it is primarily used in gaseous form. Formaldehyde is used as an effective disinfectant in the poultry industry and on farms and in hatcheries facility and transport vehicle(s). It is most important in curtailing the contamination level(s) putatively caused by bacteria, viruses and fungal organisms at various levels in the production and supply chain. It is used to reduce the load of pathogenic organisms within the hatcher that can negatively affect the embryos such as Salmonella, Escherichia coli and, Pseudomonas. It is used as an aqueous solution usually containing formalin, as a free gas, or in solid form as pellets. Formalin is a colorless liquid and exhibits slightly acidic pungent odour. To increase its effectiveness, in larger facilities, it is primarily used in gaseous form.


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Formaldehyde gas is generated by any one of the following methods:-

(a) Formaldehyde solution can be put to use by effectively vaporizing while going for fogging, spraying within a building, and in hatchers during a hatching process, to keep a check on biological contaminants.

(b) Chemical reaction of mixing formaldehyde solution with potassium permanganate (Condy’s crystals) in a metal container emits a lot of gas, which is also known as “bomb fumigation”. It can be best put to use for fumigating eggs and equipment, usually in a fumigation cabinet(s).

(c) Solid crystalline paraformaldehyde prills are heated in an electrical fry pan or similar container. This is best put to use for fumigating eggs and equipment fumigation usually within a fumigation cabinet. This is also beneficial due to very slow release over 2-3 week period when the solid crystalline paraformaldehyde prills are used in nest litter, where 10 grams lasts for approximately 14-21 days.

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All cautions needs to be taken when using formaldehyde at different facilities at farm. At breeding farm complexes and/ or annexes the person handling formaldehyde should first wear protective gear and mask having full face piece large filter respirator (rated to 100 times AES) besides, put on at least elbow length rubber gloves and overalls. The minimum protective clothing to be worn when handling paraformaldehyde prills for use as a fumigant (measuring and dispensing into electric fry pans or other heating container), is goggles, elbow length rubber gloves and overalls.

The minimum protective clothing to be worn when dispensing paraformaldehyde prills into nests is a half face piece small filter respirator (rated to 10 times AES) with goggles, elbow length rubber gloves and overalls. Alternatively a full face piece large filter respirator with gloves and overalls can be worn. Exposure to formaldehyde during normal egg collection after paraformaldehyde prills have been added to nests is normally well below the threshold limit value of 1 ppm, however light disposable non-absorbent gloves may be worn by operators if skin sensitization occurs. When spraying or fogging liquid formaldehyde (formalin) solution inside sheds the minimum protective clothing is a full face self-contained breathing apparatus as a face mask. In addition, elbow length rubber gloves and head to toe protective waterproof clothing must be worn.

Biohazards to human and animal population:

Effects of Short Term (Acute) Exposure to Formaldehyde Inhalation – Formaldehyde vapour can cause severe irritation of the nose, throat and windpipe. Tingling on the nose and throat may develop in some individuals at 0.5ppm, or even lower levels. Lachrymation occurs from 4ppm, however some individuals acclimatize to the irritant effect of formaldehyde at this level. After 30 minutes, discomfort increases considerably. More than 10 ppm can be tolerated for only a few minutes. At about 10-20 ppm breathing becomes difficult. Severe burning sensations develop in the nose, throat and windpipe, producing a cough. Serious injury is likely to occur at concentrations of about 50-100 ppm. Acute inhalation at higher concentrations has been incriminated to cause lung injury such as pulmonary oedema (a life threatening accumulation of fluid in the lungs) and pneumonitis (inflammation of the lungs) and death. The symptoms of pulmonary oedema can be delayed until hours after the exposure. Effects of Long Term (Chronic) Exposure to Formaldehyde Inhalation – Chronic exposure to formaldehyde gas may cause respiratory irritation, chronic obstruction of the airways and impaired lung function. A few reports discuss respiratory sensitisation caused by formaldehyde. These suggest that formaldehyde may be a weak lung sensitiser. Skin – Irritation and sensitisation may result from chronic exposure. Allergic reactions may produce tingling and reddening of the skin and rapid development of eczema showing red rash, scaling or cracking. Eczema may develop on the whole or portions of the face and neck and in elbow and leg creases. Sensitised workers subsequently may react to very low concentrations of formaldehyde. Medical monitoring – Pre-employment medical examinations should be undertaken if person is to be working with formaldehyde. A further medical examination should take place if acute symptoms of exposure become apparent.


Advice on dangers and first aid measures associated with the use of formaldehyde are to be clearly enunciated on notice boards within all farms and hatcheries.

(a) Skin Contact – Formaldehyde is an irritant. Repeated exposure may cause dermatitis either from irritation or allergy.

Treatment – Irrigate with plenty of water.

(b) Mucous Membrane Contact Including Eyes

Formaldehyde gas may cause severe irritation to the mucous membrane(s) of the respiratory tract and eyes.

Treatment – If splashed into the eyes, irrigate immediately with plenty of water. If swallowed drink milk or water and seek medical assistance.

(c) Inhalation – Formaldehyde is highly irritant. Discomfort will be felt at low concentration(s). If high concentrations are inhaled, coughing, difficulty in breathing, and pulmonary oedema may occur.

Treatment – Rush out to open to get fresh air immediately and perform artificial respiration if required. Seek medical assistance, immediately.


Formaldehyde should always be used by thoroughly trained experienced operators in precisely measured quantities as per indications of company. Effective regulatory measures and safety equipment must be in place to prevent the formaldehyde solution, gas or solid form coming in contact of the skin or mucous membranes (such as in the eyes, nose, mouth), and to prevent inhalation of the gas.

Read also: Drugs approved for use in conventional poultry Production 

Creating awareness through hands on training:

The person incharge be responsible for all the safety measures to be adopted for all employees in the workplace. Further, to train all the personnel who are required to store, handle and use formaldehyde in its various states. A record of each formaldehyde user’s training background shall be maintained. In addition to induction training all managers, leading hands and operators at least one annual review/training in its uses and precautions of formaldehyde application be done. Specific operating instructions be made for its use and made available at each location where it is to be used.

The purpose of highlighting the concerns in the above review is to create a healthy environment for human and animal health for a better planet for our future generations.

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