international pictogram for toxic chemicals. For substances to be regulated and handled appropriately they must be properly classified and labelled. Classification is determined by approved testing measures or calculations and has determined cut-off levels set by governments and scientists (for example, no-observed-adverse-effect levels, threshold limit values, and tolerable daily intake levels). Pesticides provide the example of well-established<unk>  class systems and<unk>  labels. While currently many countries have different regulations regarding the types of tests, numbers of tests and cut-off levels, the implementation of the Globally Harmonized System has begun unifying these countries. Global classification looks at three areas: Physical Hazards (explosions and pyrotechnics), Health Hazards and environmental hazards. Health hazards The types of<unk> es where substances may cause lethality to the entire body, lethality to specific organs, major/minor damage, or cause cancer. These are globally accepted definitions of what<unk>  is. Anything falling outside of the definition cannot be classified as that type of toxicant. Acute<unk>  Acute<unk>  looks at lethal effects following oral, dermal or inhalation exposure. It is split into five categories of severity where Category 1 requires the least amount of exposure to be lethal and Category 5 requires the most exposure to be lethal. The table below shows the upper limits for each category. Method of administration Category 1 Category 2 Category 3 Category 4 Category 5 Oral: measured in mg/kg of bodyweight 7 50 300 2 000 5 000 Dermal: LD50 measured in mg/kg of bodyweight 50 200 1 000 2 000 5 000 Gas Inhalation: LC50 measured in ppmV 100 500 2 500 20 000 Undefined Vapour Inhalation: LC50 measured in mg/L 0.5 2.0 10 20 Undefined Dust and Mist Inhalation: LC50 measured in mg/L 0.05 0.5 1.0 5.0 Undefined Note: The undefined values are expected to be roughly equivalent to the category 5 values for oral and dermal administration. Other methods of exposure and severity Skin corrosion and irritation are determined through a skin patch test analysis, similar to an allergic inflammation patch test. This examines the severity of the damage done; when it is incurred and how long it remains; whether it is reversible and how many test subjects were affected. Skin corrosion from a substance must penetrate through the epidermis into the dermis within four hours of application and must not reverse the damage within 14 days. Skin irritation shows damage less severe than corrosion if: the damage occurs within 72 hours of application; or for three consecutive days after application within a 14-day period; or causes inflammation which lasts for 14 days in two test subjects. Mild skin irritation is minor damage (less severe than irritation) within 72 hours of application or for three consecutive days after application. Serious eye damage involves tissue damage or degradation of vision which does not fully reverse in 21 days. Eye irritation involves changes to the eye which do fully reverse within 21 days. Other categories * Respiratory sensitizers cause breathing hypersensitivity when the substance is inhaled. * A substance which is a skin sensitizer causes an allergic response from a dermal application. * Carcinogens induce cancer, or increase the likelihood of cancer occurring. *Neurotoxicity is a form of<unk>  in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifically, a neurotoxin or neurotoxicant– alters the normal activity of the nervous system in such a way as to cause permanent or reversible damage to nervous tissue. * Reproductively toxic substances cause adverse effects in either sexual function or fertility to either a parent or the offspring. * Specific-target organ toxins damage only specific organs. * Aspiration hazards are solids or liquids which can cause damage through inhalation. Environmental hazards An Environmental hazard can be defined as any condition, process, or state adversely affecting the environment. These hazards can be physical or chemical, and present in air, water, and/or soil. These conditions can cause extensive harm to humans and other organisms within an ecosystem. Common types of environmental hazards * Water: detergents, fertilizer, raw sewage, prescription medication, pesticides, herbicides, heavy metals, PCBs * Soil: heavy metals, herbicides, pesticides, PCBs * Air: particulate matter, carbon monoxide, sulfur dioxide, nitrogen dioxide, asbestos, ground-level ozone, lead (from aircraft fuel, mining, and industrial processes) The EPA maintains a list of priority pollutants for testing and regulation. Occupational hazards Workers in various occupations may be at a greater level of risk for several types of<unk> , including neurotoxicity. The expression "Mad as a hatter" and the "Mad Hatter" of the book Alice in Wonderland derive from the known occupational<unk>  of hatters who used a toxic chemical for controlling the shape of hats. Exposure to chemicals in the workplace environment may be required for evaluation by industrial hygiene professionals. Hazards for small businesses Hazards from medical waste and prescription disposal Hazards in the arts Hazards in the arts have been an issue for artists for centuries, even though the<unk>  of their tools, methods, and materials was not always adequately realized. Lead and cadmium, among other toxic elements, were often incorporated into the names of artist's oil paints and pigments, for example, "lead white" and "cadmium red". 20th-century printmakers and other artists began to be aware of the toxic substances, toxic techniques, and toxic fumes in glues, painting mediums, pigments, and solvents, many of which in their labelling gave no indication of their<unk> . An example was the use of xylol for cleaning silk screens. Painters began to notice the dangers of breathing painting mediums and thinners such as turpentine. Aware of toxicants in studios and workshops, in 1998 printmaker Keith Howard published Non-Toxic Intaglio Printmaking which detailed twelve innovative Intaglio-type printmaking techniques including photo etching, digital imaging, acrylic-resist hand-etching methods, and introducing a new method of non-toxic lithography. Mapping environmental hazards There are many environmental health mapping tools. TOXMAP is a Geographic Information System (GIS) from the Division of Specialized Information Services of the United States National Library of Medicine (NLM) that uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund programs. TOXMAP is a resource funded by the US Federal Government. TOXMAP's chemical and environmental health information is taken from NLM's Toxicology Data Network (TOXNET) and PubMed, and from other authoritative sources. Aquatic<unk>  Aquatic<unk>  testing subjects key indicator species of fish or crustacea to certain concentrations of a substance in their environment to determine the lethality level. Fish are exposed for 96 hours while crustacea are exposed for 48 hours. While GHS does not define<unk>  past 100 mg/l, the EPA currently lists aquatic<unk>  as "practically non-toxic" in concentrations greater than 100 ppm. Exposure Category 1 Category 2 Category 3 Acute ≤ 1.0 mg/L ≤ 10 mg/L ≤ 100 mg/L Chronic ≤ 1.0 mg/L ≤ 10 mg/L ≤ 100 mg/L Note: A category 4 is established for chronic exposure, but simply contains any toxic substance which is mostly insoluble, or has no data for acute<unk> .
Toxicity
Neurotoxicity
Cardiotoxicity
Phototoxicity
Ototoxicity
Side effect
Acute toxicity
Hepatotoxicity