Chapter 2

Identifying the problem

Because of the different management methods required, small quantities of obsolete and unwanted pesticides should be clearly differentiated from large or bulk quantities, which are addressed in FAO’s Disposal of bulk quantities of obsolete pesticides in developing countries.5  When deciding whether a quantity of pesticides is large or small, not only should the quantity of the chemical it contains be taken into account, but also the risk it poses to health and the environment (see Table 2). The World Health Organization (WHO) has classified pesticides according to their "acute risk to health (that is, the risk of single or multiple exposures over a relatively short period of time) that might be encountered accidentally by any person handling the product in accordance with the directions for handling by the manufacturer or in accordance with the rules laid down for storage and transportation by competent international bodies".6 

All pesticide products should be labelled in accordance with the FAO Guidelines on good labelling practice for pesticides.7   The label should indicate the pesticide’s hazard rating (see Table 1) in words, symbols and an appropriately coloured band. Old and obsolete pesticides that have not been properly labelled should always be assumed to be extremely hazardous (Class Ia) according to the WHO classification system.

Table 2 provides a broad indication of the quantities that may be regarded as small, based on the WHO hazard classification of pesticides.

Any single or cumulative quantity of pesticides or contaminated materials that exceeds the amounts in Table 2 should be treated as a large or bulk quantity.

Soil, clothing or other materials that have been contaminated by pesticide, as well as empty containers, should be given the same classifications as the pesticide itself, i.e. depending on the hazard classification of the pesticide and the quantity of contaminated material or containers.

The management and disposal operations carried out should be appropriate to the total quantity of pesticides and contaminated materials present on any one site – several small quantities of individual products, containers or contaminated materials are, therefore, likely to constitute one large quantity (unless the individual amounts are very small indeed).

Unidentified products should always be assumed to be of the highest WHO hazard class and should be dealt with accordingly. These include unlabelled containers, products that have been transferred into containers other than those in which they were supplied, and materials that have been contaminated by unidentified products. If such products exceed 2.5 kg or litres they should not be dealt with as a small quantity but as a bulk quantity.

Large or bulk quantities of obsolete or unwanted pesticides should be dealt with in accordance with the FAO guidelines on the disposal of bulk quantities of obsolete pesticides in developing countries.

What causes the problem?

The following are some of the causes of accumulation of obsolete and unwanted pesticides and related waste products:

In most developing countries pesticides are expensive and difficult to obtain. Empty containers are also highly valued and are often recycled for other uses. As a result, the owners of obsolete pesticides and containers are often reluctant to declare or dispose of them – and so, when products are declared to be obsolete or unusable, their condition is likely to be extremely poor and highly hazardous. Authorities and pesticide suppliers should encourage owners to dispose of dangerous waste products.

Pesticide-related waste and empty containers will, however, continue to accumulate wherever pesticides are in use. The hazards associated with waste cannot, therefore, be eliminated by a single disposal operation and efforts should aim at reducing the generation of waste and providing long-term solutions.

The risks

Unusable pesticides pose even greater risks to people, animals and the environment than do products in good condition. Obsolete products include the many pesticides that have been banned or severely restricted because of their high toxicity or environmental persistence. Unlabelled products and pesticides that have been transferred into unmarked containers can be mistaken for other substances such as fuel, cleaning products or even drinks. Leaking containers and spilled pesticides can release noxious vapours and come into contact with other materials such as food, clothing and furniture, causing serious health problems to people or animals, even when contact has been very brief.

Pesticide product label information to indicate the WHO hazard classification
WHO hazard class

Information to appear on label

Hazard statement

Band colour

Hazard symbol

Symbols and words


Extremely hazardous

Very toxic



N Very toxic








Highly hazardous




N Toxic








Moderately hazardous












Slightly hazardous





Products unlikely to present a hazard in normal use







Definition of small quantities of pesticides, based on the WHO hazard classification of pesticides
WHO hazard class Small quantity Large quantity
Extremely hazardous (Ia)
Highly hazardous (Ib) < 2.5 kg/litre > 2.5 kg/litre
Moderately hazardous (II) < 10 kg/litre > 10 kg/litre
Slightly hazardous (III)
Less hazardous than Class III < 25 kg/litre > 25 kg/litre

5 FAO. 1996a.

6 WHO. 1998.

7 FAO. 1995c.