Toxicity Class refers to a classification system for pesticide

Pesticide

Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s that has been created by a national or international government-related or -sponsored organization. It addresses the acute toxicity

Toxicity

Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...

 of agents such as soil fumigants, fungicides, herbicides, insecticides, miticide

Miticide

Acaricides are pesticides that kill members of the Acari group, which includes ticks and mites.Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields.-Terminology:...

s, molluscicide

Molluscicide

Molluscicides, also known as snail baits and snail pellets, are pesticides against molluscs, which are usually used in agriculture or gardening to control gastropod pests like slugs and snails that can damage crops by feeding on them....

s, nematicide

Nematicide

A nematicide is a type of chemical pesticide used to kill parasitic nematodes.One common nematicide is obtained from neem cake, the residue obtained after cold-pressing the fruit and kernels of the neem tree. Known by several names in the world, the tree was first cultivated in India in ancient...

s, or rodenticides.

General considerations

Assignment to a Toxicity Class is based typically on results of acute toxicity studies such as the determination of values in animal experiments, notably rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s, via oral, inhaled, or external application. The experimental design measures the acute death rate of an agent. The Toxicity Class generally does not address issues of other potential harm of the agent, such as bioaccumulation

Bioaccumulation

Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost...

, issues of carcinogen

Carcinogen

A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...

icity, teratogenicity, mutagen

Mutagen

In genetics, a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations cause cancer, mutagens are therefore also likely to be carcinogens...

ic effects, or the impact on reproduction.

Regulating agencies may require that packaging of the agent be labeled with a Signal Word, a specific warning label to indicate the level of toxicity.

EPA (United States)

The United States Environmental Protection Agency

United States Environmental Protection Agency

The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

 uses four Toxicity Classes. Classes I to III are required to carry a Signal Word on the label. Pesticides are regulated by the Federal Insecticide, Fungicide, and Rodenticide Act

Federal Insecticide, Fungicide, and Rodenticide Act

The Federal Insecticide, Fungicide, and Rodenticide Act , et seq. is a United States federal law that set up the basic U.S. system of pesticide regulation to protect applicators, consumers, and the environment. It is administered by the Environmental Protection Agency and the appropriate...

 (FIFRA).

Toxicity Class I

• most toxic;
• requires Signal Word: "Danger-Poison", with skull and crossbones symbol, possibly followed by:

"Fatal if swallowed", "Poisonous if inhaled", "Extremely hazardous by skin contact--rapidly absorbed through skin", or "Corrosive--causes eye damage and severe skin burns"

Class I materials are estimated to be fatal to an adult human at a dose of less than 5 grams (less than a teaspoon).

Toxicity Class II

• moderately toxic
• Signal Word: "Warning", possibly followed by:

"Harmful or fatal if swallowed", "Harmful or fatal if absorbed through the skin", "Harmful or fatal if inhaled", or "Causes skin and eye irritation"

Class II materials are estimated to be fatal to an adult human at a dose of 5 to 30 grams.

Toxicity Class III

• slightly toxic
• Signal Word: Caution, possibly followed by:

"Harmful if swallowed", "May be harmful if absorbed through the skin", "May be harmful if inhaled", or "May irritate eyes, nose, throat, and skin"

Class III materials are estimated to be fatal to an adult human at some dose in excess of 30 grams.

General versus restricted use

Furthermore, the EPA classifies pesticides into those anybody can apply (General Use Pesticides), and those that must be applied by or under the supervision of a certified individual. Application of Restricted use pesticides

Restricted use pesticides

Because of safety concerns, some pesticides are not available to the general public in the United States. The "Restricted Use" classification restricts a product, or its uses, to use by a certificated pesticide applicator or under the direct supervision of a certified applicator. This means that a...

requires that a record of the application be kept.

European Union

There are three toxicity classes in the European Union

European Union

The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

's classification system, which is regulated by Directive 67/548/EEC

Directive 67/548/EEC

The Dangerous Substances Directive is one of the main European Union laws concerning chemical safety. It was made under Article 100 of the Treaty of Rome...

:

• Class I: very toxic
• Class II: toxic
• Class III: harmful
• Class IV : corrosive
• Class V : irritant
• Class VI : sensitizing
• Class VII : carcinogenic
• Class VIII : mutagenic

Very toxic and toxic substances are marked by the European toxicity symbol.

WHO

The World Health Organization

World Health Organization

The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...

names four toxicity classes:

• Class 1 – a: extremely hazardous
• Class 1 – b: highly hazardous
• Class 2: moderately hazardous
• Class 3: slightly hazardous

The system is based on LD50 determination in rats, thus an oral solid agent with an LD50 at 5mg or less/kg bodyweight is Class I-a, at 5-50 mg/kg Class I-b, at 50-500 mg/kg Class II, and at more than 500 mg/kg Class III. Values may differ for liquid oral agents and dermal agents.