Safety and Health in the Use of Agrochemicals

An ILO contribution to the International Programme on Chemical Safety 
(a collaborative programme of the United Nations Environment Programme the International Labour Organisation and the World Health Organization)

2.4. Operational control

Agrochemical users must make every effort to use those products that minimise the risk to themselves and others. In the choice of agrochemicals they may often be guided by advertisements in the mass media. It is therefore important that users seek advice from agricultural extension workers and several independent suppliers.

Similarly, choice of safe technology is important. For example, there may be several types of spray equipment on the market, but the cheapest ones are often not the best for safety. They may be of poor quality and might start to leak. The same may be true of the choice of personal protective equipment. Again, users should remember to seek advice.

The adoption of safe working systems and practices will minimise risk. Some of these have already been discussed in sections 2.3.6 and 2.3.7. The arrangement of working time, particularly in hot climates, would be relevant here. For example, agrochemical spraying could be undertaken in the early hours of the morning. Engineering control measures, personal hygiene and other measures, the use of personal protective equipment as a last line of defense and the alternatives to agrochemicals will be discussed in the following subsections.

2.4.1. Engineering control measures

A basic principle of user protection is that all possible measures should first be taken to reduce exposure at the source. Routine maintenance should ensure that agrochemical application equipment is in good condition and without any potential to leak or spill. Particular attention should be given to knapsack sprayers where leakage could seriously contaminate the user.

New developments in engineering controls go much further by introducing improved design features which automate agrochemical handling or make some tasks easier or safer.  Examples of engineering control measures include:

• Closed systems. The container is opened and the contents are automatically released through a measuring or weighing device into the spray tank.
• Filling probe. This transfers agrochemicals by suction from an opened container on the ground into the spray tank.
• Pre-mix bowl. This is a low-level bowl into which the agrochemical is poured. It is then automatically transferred to the spray tank.
• Anti-siphoning de;device. This prevents backsiphoning of spray tank contents into the water supply used for dilution or mixing.
• Easy access sprayer. Here the user can reach all parts of the sprayer for manual filling or maintenance.
• Automatic boom. In this operation the spray boom opens and folds automatically.
• Sprayer controls. These controls fitted on to the tractor are readily accessible from the driver's seat.
• Quick-change nozzles. Devices used for rapid nozzle changing and cleaning.
• Storage. Areas in the tractor designed for clean water, protective clothing, pesticide containers and spare nozzles.

Figure 32. Flow diagram of a field sprayer fitted with a pesticide induction bowl

Figure 33. A user wearing protective clothing and
filling a pre-mix bowl on a crop sprayer washed after use

2.4.2. Personal hygiene

Personal hygiene aims to keep the body clean and not allow anything harmful to remain on it for long periods as it can be absorbed through the skin. It is equally important to avoid inhaling or ingesting small, even minute, quantities of agrochemicals because of their harmful effects on health.

The basic rules of personal hygiene in using agrochemicals are as follows:

• avoid exposure to agrochemicals by following safe practices and using protective clothing and equipment when necessary;
• thoroughly wash exposed parts of the body after work, before eating, drinking or smoking, and after using the lavatory (figure 34);

Figure 34. Thoroughly wash exposed parts of the body

• examine the body regularly to ensure that the skin is clean and healthy;
• provide a protective dressing to any part of the body where there are cuts or sores;
• avoid self-contamination at all times, particularly when decontaminating or removing protective clothing;
• never attempt unsafe practices, such as blowing through sprayer nozzles to unblock them (always use a soft probe);
• do not carry contaminated items such as dirty rags, tools or spare nozzles in the pockets of personal clothing;
• remove and wash separately any contaminated item of personal protective clothing daily (figure 35);

Figure 35. Personal protective clothing should be washed after use

• keep finger-nails clean and short;
• avoid working with any product which causes an allergic response such as a skin rash.

There are other hygienic measures to be observed:

• even if the product label does not recommend
• wearing protective clothing, remember to cover
• as much of the body as possible with lightweight clothing, e.g. long-sleeved shirt; hat of towel on head; long trousers made of cloth (rather than of plastic or similar material that might cause discomfort);
• as protective clothing is uncomfortable to wear and work in, seek advice about agrochemicals that do not require the use of protective clothing. Read the label before purchasing and ask the supplier.

2.4.3. Use of personal protective equipment

Most agrochemicals present a risk to the user which may be controlled by engineering control measures. Where recourse to the above measures does not suffice, personal protective equipment should be used.

Protective clothing

Because of the nature of farm work, engineering control measures may not always be feasible. Protective clothing therefore remains a necessary part of working with agrochemicals. The items required will depend on the harmful effects of the agrochemical and the way in which it is used. In practice, labeled information supplied with the agrochemical will generally specify the level of protection required. Detailed information on the quality of various items such as the minimum thickness of gloves or the material from which they are made, e.g. neoprene, nitrile or butyl, may also be supplied. Similarly, prescribed items of respiratory protective equipment and the care necessary in their maintenance might be listed. Examples of personal protective clothing are given in figure 36, and clothing and equipment necessary when working with highly toxic agrochemicals are shown in figure 37.

Figure 36. Examples of personal protective equipment

Goggles (for eye protection) Headgear Gauntlet gloves

Respiratory protection Head, eye and face protection

Figure 37. Examples of protective clothing and equipment for work with highly toxic chemicals
Full-faced respiratory protection
Coverall
Boots (worn outside coverall)

2.4.3.1. Head protection

Head protection may be provided as a single garment or as part of a coverall or of a face shield with hood. The advantage of such a combined garment is to ensure protection around the neck or to prevent agrochemicals spilled on the hood from soiling the work clothing worn underneath. Head protection should cover all parts of the head above the shoulders, with the exception of the face. The material used should be resistant to penetration by agrochemicals.

2.4.3.2. Eye and face protection

A face shield covering the whole of the forehead and face to a point below the jaw should be worn to protect against accidental splashes of dangerous liquids during opening or pouring from containers. Non-fogging goggles resistant to chemicals should be worn when handling dusts or granules.

2.4.3.3. Respiratory protection

Respirators may be half-faced, covering nose and mouth, or full-faced, covering nose, mouth and eyes. Their function is to prevent the wearer from inhaling hazardous agrochemicals. A filtering, medium on the respirator removes the hazardous substances by absorption, adsorption or simple filtration. Filtration is by a simple gauze pad. In the case of highly hazardous agrochemicals, the air is filtered through a cartridge or canister containing other chemical substances that would absorb or adsorb the highly hazardous agrochemicals. Good respirators are manufactured to comply with national standards in several countries. The user should, however, ensure that the respirator provides a good fit around the nose and mouth and that he or she has received sufficient information and training on correct use and maintenance. The cartridges must be renewed periodically and the masks must be replaced regularly to ensure protection.

2.4.3.4. Protective gloves

Gloves are required when handling concentrated agrochemicals, particularly pesticides. These are very commonly absorbed through the skin or cause damage to the skin by burning. They should be at least 0.4 mm thick while retaining flexibility for -simple manual tasks such as opening containers or changing nozzles. The type of glove for a particular operation will depend on the agrochemical and the length of time in contact. For example, gloves of wrist length may be required for conventional spraying of toxic pesticides, elbow length for handling granules, and shoulder length for dipping plants in pesticides. A pesticide formulation with organic solvents such as xylene will require a glove of much higher-quality material because of its capacity to penetrate protective garments.

An indication of protective glove performance when tested against three groups of agrochemicals is given in Annex D.

2.4.3.5. Working clothes

Working clothes are items of personal clothing worn at work, while using agrochemicals, in this instance. They include such items as shirts, trousers,, skirts, socks and shoes or boots. There will be many occasions when working clothes will be the main skin covering, e.g. when using low risk products or treating an animal.

Working clothes used at work with agrochemicals should be kept clean by washing immediately after use. Wearing clothes contaminated with agrochemicals: may result in poisoning or skin irritation. There have also been cases where flammable substances, such as sodium chlorate, deposited on clothes have ignited during cigarette smoking to engulf both clothing and the wearer in flames.

In general, working clothes should:

• fit comfortably so that free movement of the body and limbs is possible without undue restraint;
• be worn by the same person each day and not exchanged between individuals;
• be in good condition, sewn or mended when necessary;
• be clean and free of agrochemical deposits. Soiled work clothing should be cleaned separately from the family wash;
• be worn under protective clothing so that it is completely covered and not exposed to accidental contamination;
• be stored separately from protective clothing so that cross-contamination is avoided.

2.4.3.6. Selection, use and maintenance of personal protective equipment

When specified on the product label, the selection of appropriate personal protective equipment, its use and maintenance are essential for the protection of a person using hazardous agrochemicals. Advice should be sought (figure 38) and particular attention paid to the following:

Figure 38. Select the appropriate type of personal
protective equipment (ask someone who knows)

• Resistance to agrochemicals. Protective clothing is produced in a variety of material with varying capacity to resist penetration. The user should seek advice and select the appropriate ones by reading the instructions on the label or asking the supplier. In general, garments such as gloves made from neoprene, nitrile or viton material of at least 0.4 mm in thickness are resistant to most agrochemical formulations. Similarly, boots and aprons which are intended to resist contamination by concentrates should be equally resistant. Coveralls should be impermeable to liquids if subject to high levels of contamination, e.g. when the user is beneath the trees while spraying "top fruit". If exposure is limited to occasional liquid spills or to dry powders or granules, a coverall made of a fabric material such as treated cotton or polyester may be sufficient.
• Choice of garments. Some garments, such as gloves or hats made from cotton, canvas, felt or leather, are particularly unsafe for use as protective equipment during work with very hazardous agrochemicals because they absorb liquids. These liquids in turn are absorbed through the skin of the wearer, resulting in poisoning. Clothing may also be unsafe because of repeated use which may wrinkle the protective surface, allowing liquids to seep through: it should be discarded as soon as a defect becomes noticeable. Some protective clothing is intended for other purposes, such as gloves for protection against detergents at home or in the kitchen. This type of clothing may be unsuitable for work with very hazardous agrochemicals, and advice should be sought.

Tailoring. Garments should preferably be made to measure, or ready-made ones should be well selected so that seams or welded joints do not pull apart or allow liquids to enter through stitch holes. There should be no trap points which hold agrochemicals and all pockets should be inside the garment or absent altogether. Garments should provide a good cover to those parts of the body which they are intended to protect. They should also allow freedom of movement to the wearer.

Correct matching. In practice, several items of protective clothing are often worn at the same time. Each should be a correct match with the other in providing continuity of protection between, for example, a hood overlapping the shoulders of a coverall, the sleeves of the coverall overlapping gloves, and an apron overlapping boot tops.

User friendliness. Protective clothing should not prevent the wearer from carrying out the necessary tasks associated with agrochemical- work. Gloves should not be so big or rigid that the fingers cannot be manipulated to replace a sprayer nozzle. It should be possible for the wearer to move freely without being hindered by the sheer bulk or poor design of any garment. Similarly, garments should not be unduly heavy or hot when worn. Those for use in tropical countries should wherever possible be of lightweight material and coloured white or yellow so as to reflect heat. Users should learn how to select the appropriate protective equipment.

Washabifty. All garments used at work with agrochemicals: should be washable without any substance being retained in "trap points". Absorbent garments such as untreated cotton may be particularly difficult to clean completely.

Suitability. Each item of protective clothing should be suitable for its circumstances of use. Respirators, in particular, should be of a type approved by a responsible authority. They should be fitted with the appropriate cartridge or filter to give protection against the particular hazard. There are many different types of respirator. These include

• those which are disposable and give protection against dust, fumes and mist;
• chemical cartridge types;
• canister types;
• fully self-contained types; and
• airline breathing units.

The safe use of respirators depends upon a thorough knowledge of

• how to wear them correctly;
• recognising that they fit the worker accurately; and
• the precautions to be observed.

The user should receive specific training in all these aspects. There may be circumstances where there would be a choice of garments. These may include gauntlet gloves in preference to the shorter hand gloves, hats with broad rims or hoods, and goggles which are non-fogging. Advice should be sought.

Making a clean start. Clothing to be worn at the start of each day should be clean, dry and in good condition. The various items should be checked for signs of wear and tear and repaired or replaced as necessary.

Wearing correctly. When gloves are worn with an impermeable coverall, it is good practice to wear the cuffs of the gloves inside the shirt sleeves so that run-off of liquids sprayed does not drip inside the gloves. Similarly, the legs of coveralls should normally be worn outside boots so that run-off drips outside. Other garments should also be worn properly. This may include the correct fastening of buttons and zips and having face shields properly lowered into position (figure 39).

Figure 39. Protective clothing and equipment
should be worn and used correctly

Decontamination after use. Gloves and boots should be washed before removal to avoid self-contamination (figure 40). They should then be removed and the inside should be thoroughly washed with water and detergent, rinsed and allowed to dry. Goggles and face masks should be similarly washed and allowed to dry.

Figure 40. Boots used during agrochemical application
must be washed before removal to prevent contamination

Safe storage. Protective clothing should be stored in a clean, dry, well-ventilated room separate from other clothing or living accommodation (figure 41).

Figure 41. Protective clothing and equipment
should be stored in separate accommodation

The FAO Guidelines for personal protection when working with pesticides in tropical climates (in preparation) will provide more detailed information.

2.4.4. The use of alternatives to agrochemicals

Good agricultural practice recognises the importance of agrochemicals. When used correctly, they contribute to an improvement in agricultural production. However, excessive or indiscriminate use of agrochemicals may lead to health hazards, and damage to crops, livestock, wildlife and the environment. Alternatives to a dependence on agrochemicals may include the following:

• Cultural controls. This is essentially the use of cultivation techniques for the benefit of the crop and to the disadvantage of pests of any kind. Crop rotation is the most effective cultural control. It avoids a build-up of crop-specific pests and a depletion of the plant nutrients in the soil. Crop rotation is also beneficial. It replenishes soil nutrients with decayed organic matter, improves the soil structure and helps weeding.
• Biological controls. The natural enemies of pests are known as insect predators. Biological controls seek to encourage those insect predators which are harmless to the crop but which destroy the pests in the same way as agrochemical insecticides. Insect predators are a valuable alternative to agrochemicals and may be bred in captivity for a timely release to control an insect population.
• Breeding of pest-resistant plants. Plant breeding seeks to develop improved varieties of crops such as rice, wheat and maize, which will respond well to cultivation and produce good yields. A resistance to crop diseases, particularly those caused by micro-organisms such as viruses, fungi and bacteria, is an important part of this process. Information obtained during the breeding programme will also indicate ideal growing conditions and will be of value to the farmer. This may include information on nutritional requirements, planting density or the best time for planting and harvesting so as to avoid insect damage. Farmers should seek advice on varieties of crops resistant to pests in their locality.
• Physical controls. Traps have a long history of use in the capture of various pests. They may be snares, or cages for vertebrates such as rats, rabbits and birds, or sticky tape, swats and lures for invertebrates such as snails, flies and other insects. In recent years these methods have become more sophisticated by including electronic triggering devices or the use of electricity as a light source. Pests attracted to hot electric bulbs get burnt. Physical controls are very useful in dealing with relatively small infestations of rodents or other pests, for example in food processing areas where agrochemicals should not be used.
• Integrated controls. This is a combination of several control measures described above, plus the controlled use of agrochemicals. The measures are balanced with one another so as to obtain the best results. The practical implementation of integrated controls will often depend on circumstances. The component parts may be balanced differently according to cost, opportunity and the way in which a crop is threatened. In practice, integrated controls are commonly used as part of good agricultural practice throughout the world and are continuing to be developed as part of integrated pest management programmes.

In some countries different control methods will be subject to national standards that regulate the way in which the controls may be used.

2.4.5. Prevention of poisoning

The prevention of poisoning depends upon a responsible attitude of the user under all circumstances of use. Before beginning agrochemical application the user should read, understand and follow the information on the label, check the suitability of equipment, and ensure that he or she has the necessary competence. The user's responsibility will end only after use. Every item used should be safely decontaminated and any surplus returned to the store. Taken together the precautionary measures may be summarised as follows:

• Use the least poisonous product. Where there is a choice of different agrochemicals, the one selected should be the least poisonous.
• Use as directed. The agrochemical should be used only for the purpose for which it was intended and in compliance with the recommendations on the label.
• Observe the precautions on the label. Comply with such matters as protective clothing to be worn, application rates, re-entry period and protection of the general public.
• Control exposure at source. Where exposure can be controlled by an engineering control measure, this should be done first. Examples may include the use of closed systems, pre-mix bowls and suction probes, and the correct maintenance and repair of agrochemical application equipment.
• Comply with the law. Where legislation is in force to control the use of agrochemicals, this should be complied with.
• Avoid unsafe practices. Agrochemicals should be used with a sense of responsibility towards humans, animals and the environment. Irresponsible behaviour of any kind should be condemned and prohibited.
• Education. Training in the use of agrochemicals is necessary to develop the competence of the user. A knowledge of basic precautionary measures to prevent accidental poisoning should be included in training.
• Cleanliness. Protective clothing and equipment should be decontaminated after use, and inspected to see if any item needs repair or replacement. Unused agrochemicals should be returned to the store and empty containers disposed of safely.
• Attention to personal hygiene. Physical cleanliness, particularly after work and at mealtimes, will avoid absorption of agrochemicals due to careless use that could cause ill-health.
• Seeking medical attention. If poisoning is suspected, medical attention should be obtained as soon as possible in order to avoid a more serious illness. Remember the name of the product involved and tell the doctor, if for any reason it is not possible to take the labeled container of the product used. The doctor can then give prompt treatment or may seek advice, for example from a poison information centre.

2.5. Other applications

2.5.2. Work in greenhouses and similar structures

There are special problems associated with work in greenhouses (figure 42), where agrochemicals are used in a wide variety of circumstances. These may include the controlled feeding of plants with liquid nutrients, or the release of carbon dioxide to assist plant growth or as pesticides for crop protection.

Figure 42. Work in a greenhouse involves many risks associated with agrochemicals

To some extent agrochemical use under a protective covering has advantages; the user is insulated against wind and other weather conditions. There are, however, disadvantages such as the following, which require special consideration:

• Plant congestion. There is less space for maneuver within a building because growing plants are kept close together in order to maximise all available space. This increases the possibility of physical contact with treated surfaces and reinforces the need for adequate personal protection.
• Frequency of application. Fast-growing covered plants will generally need a more frequent application of agrochemicals than those growing in the open. There will also be a tendency to use several different, but similar pesticides in order to overcome insect resistance to a particular active ingredient. All this will increase the user's frequency of exposure to a wide range of agrochemicals and will call for a high standard of personal hygiene and strict compliance with precautionary measures.
• Low ventilation. Greenhouse ventilation is set to promote plant growth and is generally poor for the user. It is important to allow for this in determining re-entry times after spraying, particularly where spray droplets may have vapourised after settling on heating pipes or similar hot surfaces.
• Close body contact with applicator. Some agrochemical applicators, such as knapsack sprayers, are carried in greenhouses. Particular care should be taken because of the confined space. Inhalation risk is greater because the vapour concentration from any leaks or spills will be higher. Spray equipment should be properly serviced and repaired when necessary.
• Wear and tear of protective clothing. The regular use of protective clothing requires a more frequent rate of servicing and replacement. Facilities for decontamination, washing and storage should also be available.
• Re-entry. The use of pesticides as fumigants, mists or fog will make it dangerous for anyone to enter a building for some time afterwards. In these circumstances the building should be securely locked and a warning notice posted outside.

2.5.2. Aerial spraying

Agrochemicals, particularly pesticides and . fertilisers, are sometimes applied from helicopters and fixed-wing aircraft (figure 43). This is a common practice in plantations in several countries. The national aviation authority that permits the use of these aircraft prescribes additional controls when they are used for aerial spraying. These requirements have already been published by the ILO. Some basic principles are listed in this guide.

Figure 43. Aerial spraying of pesticides

The national aviation authority should specify:

• the levels of competence necessary for pilots and ground crews;
• a restricted list of only those pesticides which may be applied, together with further conditions on their approved circumstances of use and the precautions to be observed;
• prior consultations with persons responsible for potable water and land areas such as any kind of public or farm livestock water supply, water used for farming or rearing of aquatic life, or water used for the irrigation of crops or land on which there are susceptible plants or wildlife;
• that the following persons be notified:
  • public authorities such as police, public health 3.8 or enforcement agencies;
  • hospital authorities, schools or other institutions in the vicinity of the aerial spraying site;
  • the occupants of any building and persons responsible for livestock or crops surrounding the site;
  • any keeper of pollinating insects such as bees
• that warning signs be erected and ground markers employed;
• that records be maintained.

Discussion and activities
(sections 2.4 and 2.5)

1. Identify the safety devices on the equipment that you use for agrochemical spraying. List them separately.

2. List ten basic rules of personal hygiene.

3. Personal protective equipment

• List the items of personal protective equipment that you use. Give the name and address of the retailer and date of purchase.
• When did you last inspect it?
• How do you ensure that each item has been properly cleaned? Do you keep a record?
• Who has trained you in the use of each kind of equipment?
• How do you ensure that you use the right equipment for each hazardous operation?
• Are you trained to check that each item is giving you adequate protection? If not, remember that it is a risk to use it, as it would give only a sense of false protection. Consult someone who knows.
• What discomfort do you experience working with personal protective equipment?
• Have you tried changing the time of day of application of chemicals, for example, by working very early in the morning when wearing the equipment? What is your experience?
• Discuss with your trainer possible alternatives to working with personal protective equipment when spraying dilute solutions of pesticides, e.g. using a plastic bag to replace gloves; using smaller quantities and spraying for a quarter or less of the time.

4. What is integrated pest control?

• Have you any experience of using other methods of pest control? Describe it.
• List examples of larger insects or animals that feed on your pests on the farm.

5. List eight precautionary measures you should take in organising the prevention of agrochemical poisoning.

6. If you have any experience of aerial spraying or working in greenhouses, explain to others in the group:

• the various risks involved; and
• the precautions you have been instructed to take.