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Saturday, October 15, 2022

Tree of life

From Wikipedia, the free encyclopedia

An 1847 depiction of the Norse Yggdrasil as described in the Icelandic Prose Edda by Oluf Olufsen Bagge
 
17th-century depiction of the tree of life in Palace of Shaki Khans, Azerbaijan
 
Confronted animals, here ibexes, flank a tree of life, a very common motif in the art of the ancient Near East and Mediterranean

The tree of life is a fundamental archetype in many of the world's mythological, religious, and philosophical traditions. It is closely related to the concept of the sacred tree. The concept of the tree of life may have originated in Central Asia, and absorbed by other cultures, such Scandinavian mythology and Altai shamanism.

The tree of knowledge, connecting to heaven and the underworld, and the tree of life, connecting all forms of creation, are both forms of the world tree or cosmic tree, and are portrayed in various religions and philosophies as the same tree. Trees promote health and social well-being by removing air pollution, reducing stress, encouraging physical activities, and promoting social ties and community.

Religion and mythology

Various trees of life are recounted in folklore, culture and fiction, often relating to immortality or fertility. They had their origin in religious symbolism. According to professor Elvyra Usačiovaitė, a "typical" imagery preserved in ancient iconography is that of two symmetrical figures facing each other, with a tree standing in the middle. The two characters may variously represent rulers, gods, and even a deity and a human follower.

Ancient Mesopotamia

Assyrian tree of life, from Nimrud panels.

The Assyrian tree of life was represented by a series of nodes and criss-crossing lines. It was apparently an important religious symbol, often attended to in Assyrian palace reliefs by human or eagle-headed winged genies, or the King, and blessed or fertilized with bucket and cone. Assyriologists have not reached consensus as to the meaning of this symbol. The name "Tree of Life" has been attributed to it by modern scholarship; it is not used in the Assyrian sources. In fact, no textual evidence pertaining to the symbol is known to exist.

The Urartian tree of life

The Epic of Gilgamesh is a similar quest for immortality. In Mesopotamian mythology, Etana searches for a 'plant of birth' to provide him with a son. This has a solid provenance of antiquity, being found in cylinder seals from Akkad (2390–2249 BCE).

Urartu

In ancient Urartu, the tree of life was a religious symbol and was drawn on walls of fortresses and carved on the armor of warriors. The branches of the tree were equally divided on the right and left sides of the stem, with each branch having one leaf, and one leaf on the apex of the tree. Servants stood on each side of the tree with one of their hands up as if they are taking care of the tree.

Ancient Iran

Tree of life on a rhyton from Marlik, Iran, currently at the National Museum of Iran.

In the Avestan literature and Iranian mythology, there are several sacred vegetal icons related to life, eternality and cure, like: Amesha Spenta Amordad (guardian of plants, goddess of trees and immortality), Gaokerena (or white Haoma) a tree that its vivacity would certify continuance of life in universe, Bas tokhmak (a tree with remedial attribute, retentive of all herbal seeds, and destroyer of sorrow), Mashyа and Mashyane (parents of the human race in Iranian myths), Barsom (copped offshoots of pomegranate, gaz or Haoma that Zoroastrians use in their rituals), Haoma (a plant, unknown today, that was source of sacred potable), etc.

Gaokerena is a large, sacred Haoma planted by Ahura Mazda. Ahriman (Ahreman, Angremainyu) created a frog to invade the tree and destroy it, aiming to prevent all trees from growing on the earth. As a reaction, Ahura Mazda created two kar fish staring at the frog to guard the tree. The two fish are always staring at the frog and stay ready to react to it. Because Ahriman is responsible for all evil including death, while Ahura Mazda is responsible for all good (including life).

Haoma is another sacred plant due to the drink made from it. The preparation of the drink from the plant by pounding and the drinking of it are central features of Zoroastrian ritual. Haoma also personified as a divinity. It bestows essential vital qualities—health, fertility, husbands for maidens, even immortality. The source of the earthly haoma plant is a shining white tree that grows on a paradisiacal mountain. Sprigs of this white haoma were brought to earth by divine birds. The tree is considerably diverse.

Haoma is the Avestan form of the Sanskrit soma. The near identity of the two in ritual significance is considered by scholars to point to a salient feature of an Indo-Iranian religion antedating Zoroastrianism.

Another related issue in ancient mythology of Iran is the myth of Mashyа and Mashyane, two trees who were the ancestors of all living beings. This myth can be considered as a prototype for the creation myth where living beings are created by Gods (who have a human form).

Chinese mythology

Bronze Tree with birds, flowers, and ornaments from Sanxingdui
 

In Chinese mythology, a carving of a tree of life depicts a phoenix and a dragon; the dragon often represents immortality. A Taoist story tells of a tree that produces a peach of immortality every three thousand years, and anyone who eats the fruit receives immortality.

An archaeological discovery in the 1990s was of a sacrificial pit at Sanxingdui in Sichuan, China. Dating from about 1200 BCE, it contained three bronze trees, one of them 4 meters high. At the base was a dragon, and fruit hanging from the lower branches. At the top is a bird-like (Phoenix) creature with claws. Also found in Sichuan, from the late Han dynasty (c 25 – 220 CE), is another tree of life. The ceramic base is guarded by a horned beast with wings. The leaves of the tree represent coins and people. At the apex is a bird with coins and the Sun.

Christianity

Allegorical painting of the Tree of Life in the Church of San Roque of Arahal (Seville). Oil on canvas by anonymous author. Dated 1723
 

The tree of life first appears in Genesis 2:9 and 3:22-24 as the source of eternal life in the Garden of Eden, from which access is revoked when man is driven from the garden. It then reappears in the last book of the Bible, the Book of Revelation, and most predominantly in the last chapter of that book (Chapter 22) as a part of the new garden of paradise. Access is then no longer forbidden, for those who "wash their robes" (or as the textual variant in the King James Version has it, "they that do his commandments") "have right to the tree of life" (v.14). A similar statement appears in Rev 2:7, where the tree of life is promised as a reward to those who overcome. Revelation 22 begins with a reference to the "pure river of water of life" which proceeds "out of the throne of God". The river seems to feed two trees of life, one "on either side of the river" which "bear twelve manner of fruits" "and the leaves of the tree were for healing of the nations" (v.1-2). Or this may indicate that the tree of life is a vine that grows on both sides of the river, as John 15:1 would hint at.

Pope Benedict XVI has said that "the Cross is the true tree of life." Saint Bonaventure taught that the medicinal fruit of the tree of life is Christ himself. Saint Albert the Great taught that the Eucharist, the Body and Blood of Christ, is the Fruit of the Tree of Life. Augustine of Hippo said that the tree of life is Christ:

All these things stood for something other than what they were, but all the same they were themselves bodily realities. And when the narrator mentioned them he was not employing figurative language, but giving an explicit account of things which had a forward reference that was figurative. So then the tree of life also was Christ... and indeed God did not wish the man to live in Paradise without the mysteries of spiritual things being presented to him in bodily form. So then in the other trees he was provided with nourishment, in this one with a sacrament... He is rightly called whatever came before him in order to signify him.

In Eastern Christianity the tree of life is the love of God.

The Church of Jesus Christ of Latter-day Saints

The tree of life vision is described and discussed in the Book of Mormon. According to the Book of Mormon, the vision was received in a dream by the prophet Lehi, and later in vision by his son Nephi, who wrote about it in the First Book of Nephi. The vision includes a path leading to a tree, the fruit of the tree symbolizing the love of God, with an iron rod, symbolizing the word of God, along the path whereby followers of Jesus may hold to the rod and avoid wandering off the path into pits or waters symbolizing the ways of sin. The vision also includes a large building wherein the wicked look down at the righteous and mock them.

The vision is said to symbolize love of Christ and the way to eternal life and is a well known and cited story with members of The Church of Jesus Christ of Latter-day Saints. A member of the church reflected that the vision is "one of the richest, most flexible, and far-reaching pieces of symbolic prophecy contained in the standard works [scriptures]."

Nag Hammadi Gnosticism

Different views on the Tree of life can be found in the Nag Hammadi library codices, writings belonging to Gnosticism. In On the Origin of the World, the Tree of Life is said to be located to the north of paradise, providing life to the innocent saints who will come out of their material bodies during what is called the consummation of the age. The color of the tree is described as resembling the Sun, its branches are beautiful, its leaves are similar to that of cypress, and its fruit is like clusters of white grapes. However, in the Secret Book of John, the Tree of Life is portrayed negatively. Its roots are described as bitter, its branches are death, its shadow is hatred, a trap is found in its leaves, its seed is desire, and it blossoms in the darkness.

Manichaeism

Manichaeans worshiping the Tree of Life in the Realm of Light. Mid 9th — early 11th century.

In the Gnostic religion Manichaeism, the Tree of Life helped Adam obtain the knowledge (gnosis) necessary for salvation and is identified as an image of Jesus.

Europe

In Greek mythology, Hera is gifted a branch growing golden apples by her grandmother Gaia, which are then planted in Hera's Garden of the Hesperides. The dragon Ladon guards the tree(s) from all who would take the apples. The three golden apples that Aphrodite gave to Hippomenes to distract Atalanta three times during their footrace allowed him to win Atalanta's hand in marriage. Though it is not specified in ancient myth, many assume that Aphrodite gathered those apples from Hera's tree(s). Eris stole one of these apples and carved the words ΤΗΙ ΚΑΛΛΙΣΤΗΙ, "to the fairest", upon it to create the Apple of Discord. Heracles retrieve three of the apples as the eleventh of his Twelve Labors. The Garden of the Hesperides is often compared to Eden, the golden apples are compared to the forbidden fruit of the tree in Genesis, and Ladon is often compared to the snake in Eden, all of which is part of why the forbidden fruit of Eden is usually represented as an apple in European art, even though Genesis does not specifically name nor describe any characteristics of the fruit.

11th century tree of life sculpture at an ancient Swedish church

In Dictionnaire Mytho-Hermetique (Paris, 1737), Antoine-Joseph Pernety, a famous alchemist, identified the tree of life with the Elixir of life and the Philosopher's Stone.

In Eden in the East (1998), Stephen Oppenheimer suggests that a tree-worshipping culture arose in Indonesia and was diffused by the so-called "Younger Dryas" event of c. 10,900 BCE or 12,900 BP, after which the sea level rose. This culture reached China (Szechuan), then India and the Middle East. Finally the Finno-Ugric strand of this diffusion spread through Russia to Finland where the Norse myth of Yggdrasil took root.

The Celtic god Lugus was associated with the Celtic version of the tree of life.

Georgia

The Borjgali (Georgian: ბორჯღალი) is an ancient Georgian tree of life symbol.

Germanic paganism and Norse mythology

In Germanic paganism, trees played (and, in the form of reconstructive Heathenry and Germanic Neopaganism, continue to play) a prominent role, appearing in various aspects of surviving texts and possibly in the name of gods.

The tree of life appears in Norse religion as Yggdrasil, the world tree, a massive tree (sometimes considered a yew or ash tree) with extensive lore surrounding it. Perhaps related to Yggdrasil, accounts have survived of Germanic Tribes honouring sacred trees within their societies. Examples include Thor's Oak, sacred groves, the Sacred tree at Uppsala, and the wooden Irminsul pillar. In Norse Mythology, the apples from Iðunn's ash box provide immortality for the gods.

Islam

Carpet tree of life
 

The "Tree of Immortality" (Arabic: شجرة الخلود) is the tree of life motif as it appears in the Quran. It is also alluded to in hadiths and tafsir. Unlike the biblical account, the Quran mentions only one tree in Eden, also called the tree of immortality and ownerships which decays not, which Allah specifically forbade to Adam and Eve. The tree in Quran is used as an example for a concept, idea, way of life or code of life. A good concept/idea is represented as a good tree and a bad idea/concept is represented as a bad tree Muslims believe that when God created Adam and Eve, he told them that they could enjoy everything in the Garden except this tree(idea, concept, way of life), and so, Satan appeared to them and told them that the only reason God forbade them to eat from that tree is that they would become Angels or they start using the idea/concept of Ownership in conjunction with inheritance generations after generations which Iblis convinced Adam to accept The hadiths also speak about other trees in heaven. When they ate from this tree their nakedness appeared to them and they began to sew together, for their covering, leaves from the Garden.

The tree of life in Islamic architecture is a type of biomorphic pattern found in many artistic traditions and is considered to be any vegetal pattern with a clear origin or growth. The pattern in Al Azhar mosque, Cairo's mihrab, a unique Fatimid architectural variation, is a series of two or three leave palmettes with a central palmette of five leaves from which the pattern originates. The growth is upwards and outwards and culminates in a lantern like flower towards the top of the niche above which is a small roundel. The curvature of the niche accentuates the undulating movement which despite its complexity is symmetrical along its vertical axis. The representations of varying palm leaves hints to spiritual growth attained through prayer while the upwards and side wards movement of the leaves speaks to the different motions of the worshiper while in salah.

Ahmadiyya

According to the Indian Ahmadiyya movement founded in 1889, Quranic reference to the tree is symbolic; eating of the forbidden tree signifies that Adam disobeyed God.

Jewish sources

Etz Chaim, Hebrew for "tree of life," is a common term used in Judaism. The expression, found in the Book of Proverbs, is figuratively applied to the Torah itself. Etz Chaim is also a common name for yeshivas and synagogues as well as for works of Rabbinic literature. It is also used to describe each of the wooden poles to which the parchment of a Sefer Torah is attached.

The tree of life is mentioned in the Book of Genesis; it is distinct from the tree of the knowledge of good and evil. After Adam and Eve disobeyed God by eating fruit from the tree of the knowledge of good and evil, they were driven out of the Garden of Eden. Remaining in the garden, however, was the tree of life. To prevent their access to this tree in the future, Cherubim with a flaming sword were placed at the east of the garden.

In the Book of Proverbs, the tree of life is associated with wisdom: "[Wisdom] is a tree of life to them that lay hold upon her, and happy [is every one] that retaineth her." In Proverbs 15:4, the tree of life is associated with calmness: "A soothing tongue is a tree of life; but perverseness therein is a wound to the spirit."

In the Ashkenazic liturgy, the Eitz Chayim is a piyyut commonly sung as the Sefer Torah is returned to the Torah ark.

The Book of Enoch, generally considered non-canonical, states that in the time of the great judgment, God will give all those whose names are in the Book of Life fruit to eat from the tree of life.

Kabbalah

Judaic Kabbalah tree of life 10 Sefirot, through which the Ein Sof unknowable divine manifests Creation. The configuration relates to man

Jewish mysticism depicts the tree of life in the form of ten interconnected nodes, as the central symbol of the Kabbalah. It comprises the ten Sefirot powers in the divine realm. The panentheistic and anthropomorphic emphasis of this emanationist theology interpreted the Torah, Jewish observance, and the purpose of Creation as the symbolic esoteric drama of unification in the Sefirot, restoring harmony to Creation. From the time of the Renaissance onwards, Jewish Kabbalah became incorporated as an important tradition in non-Jewish Western culture, first through its adoption by Christian Kabbalah, and continuing in Western esotericism occult Hermetic Qabalah. These adapted the Judaic Kabbalah tree of life syncretically by associating it with other religious traditions, esoteric theologies, and magical practices.

Mandaeism

Mandaean scrolls often include abstract illustrations of trees of life that represent the living, interconnected nature of the cosmos.

Mesoamerica

The concept of world trees is a prevalent motif in pre-Columbian Mesoamerican cosmologies and iconography. World trees embodied the four cardinal directions, which represented also the fourfold nature of a central world tree, a symbolic axis mundi connecting the planes of the Underworld and the sky with that of the terrestrial world.

Depictions of world trees, both in their directional and central aspects, are found in the art and mythological traditions of cultures such as the Maya, Aztec, Izapan, Mixtec, Olmec, and others, dating to at least the Mid/Late Formative periods of Mesoamerican chronology. The tomb for the Ancient Maya king, K'inich Janab' Pakal I of Palenque who became King at only 12 years old has Tree of Life Inscriptions within the walls of his burial place, showing just how important it was to the Maya people. Among the Maya, the central world tree was conceived as or represented by a ceiba tree, and is known variously as a wacah chan or yax imix che, depending on the Mayan language. The trunk of the tree could also be represented by an upright caiman, whose skin evokes the tree's spiny trunk.

Directional world trees are also associated with the four Yearbearers in Mesoamerican calendars, and the directional colors and deities. Mesoamerican codices which have this association outlined include the Dresden, Borgia and Fejérváry-Mayer codices. It is supposed that Mesoamerican sites and ceremonial centers frequently had actual trees planted at each of the four cardinal directions, representing the quadripartite concept.

World trees are frequently depicted with birds in their branches, and their roots extending into earth or water (sometimes atop a "water-monster," symbolic of the underworld). The central world tree has also been interpreted as a representation of the band of the Milky Way.

North America

In a myth passed down among the Iroquois, The World on the Turtle's Back, explains the origin of the land in which a tree of life is described. According to the myth, it is found in the heavens, where the first humans lived, until a pregnant woman fell and landed in an endless sea. Saved by a giant turtle from drowning, she formed the world on its back by planting bark taken from the tree.

The tree of life motif is present in the traditional Ojibway cosmology and traditions. It is sometimes described as Grandmother Cedar, or Nookomis Giizhig in Anishinaabemowin.

In the book Black Elk Speaks, Black Elk, an Oglala Lakota (Sioux) wičháša wakȟáŋ (medicine man and holy man), describes his vision in which after dancing around a dying tree that has never bloomed he is transported to the other world (spirit world) where he meets wise elders, 12 men and 12 women. The elders tell Black Elk that they will bring him to meet "Our Father, the two-legged chief" and bring him to the center of a hoop where he sees the tree in full leaf and bloom and the "chief" standing against the tree. Coming out of his trance he hopes to see that the earthly tree has bloomed, but it is dead.

The Oneidas tell that supernatural beings lived in the Skyworld above the waters which covered the earth. This tree was covered with fruits which gave them their light, and they were instructed that no one should cut into the tree otherwise a great punishment would be given. As the woman had pregnancy cravings, she sent her husband to get bark, but he accidentally dug a hole to the other world. After falling through, she came to rest on the turtle's back, and four animals were sent out to find land, which the muskrat finally did.

Serer religion

In Serer religion, the tree of life as a religious concept forms the basis of Serer cosmogony. Trees were the first things created on Earth by the supreme being Roog (or Koox among the Cangin). In the competing versions of the Serer creation myth, the Somb (Prosopis africana) and the Saas tree (acacia albida) are both viewed as trees of life. However, the prevailing view is that, the Somb was the first tree on Earth and the progenitor of plant life. The Somb was also used in the Serer tumuli and burial chambers, many of which had survived for more than a thousand years. Thus, Somb is not only the tree of life in Serer society, but the symbol of immortality.

Turkic

The tree of life, as seen as in flag of Chuvashia, a Turkic state in the Russian Federation

The tree of life connects the upper world, middle world and underworld. It is also imagined as the "white creator lord" (yryn-al-tojon), thus synonymous with the creator deity, giving raise to different worlds. The world tree or tree of life is an important symbol in Turkic mythology. It is a common motif in carpets. It is used in the logo of the Ministry of Culture and Tourism (Turkey) and in 2009 it was introduced as the main design of the common Turkish lira sub-unit 5 kuruş.

Tree of life is known as Ulukayın or Baiterek in Turkic communities. It is a sacred beech tree planted by Kayra Han. Sometimes, it is considered axis mundi.

Hinduism

In the sacred books of Hinduism (Sanātana Dharma), Puranas mention a divine tree Kalpavriksha. This divine tree is guarded by Gandharvas in the garden of Amaravati city under the control of Indra, King of gods. In one story, for a very long time, gods and demi-gods who are believed to be fathered by Kashyapa Prajapati and have different mothers. After a long time frequent battles between the two half-brother clans, both groups decided to churn the milky ocean to obtain Amrutham and share equally. During the churning, along with many other mythical items emerged the Kalpavruksham. It is gold in colour. It has mesmerizing aura. It can be pleased with chanting and offers. When it is pleased, it grants every wish.

Nonetheless Hindu tradition holds that there are five separate kalpavrikshas and each of them grant different types of wishes. Accordingly these trees also appear in the beliefs of Jainism.

Baháʼí Faith

The concept of the tree of life appears in the writings of the Baháʼí Faith, where it can refer to the Manifestation of God, a great teacher who appears to humanity from age to age. An example of this can be found in the Hidden Words of Bahá'u'lláh:

"Have ye forgotten that true and radiant morn, when in those hallowed and blessed surroundings ye were all gathered in My presence beneath the shade of the tree of life, which is planted in the all-glorious paradise? Awestruck ye listened as I gave utterance to these three most holy words: O friends! Prefer not your will to Mine, never desire that which I have not desired for you, and approach Me not with lifeless hearts, defiled with worldly desires and cravings. Would ye but sanctify your souls, ye would at this present hour recall that place and those surroundings, and the truth of My utterance should be made evident unto all of you."

Also, in the Tablet of Ahmad of Bahá'u'lláh: "Verily He is the Tree of Life, that bringeth forth the fruits of God, the Exalted, the Powerful, the Great".

Bahá'u'lláh refers to his male descendants as branches (Arabic: ﺍﻏﺼﺎﻥ ʾaghṣān) and calls women leaves.

A distinction has been made between the tree of life and the tree of the knowledge of good and evil. The latter represents the physical world with its opposites, such as good and evil and light and dark. In a different context from the one above, the tree of life represents the spiritual realm, where this duality does not exist.

In art and film

Austrian symbolist artist Gustav Klimt portrayed his version of the tree of life in his painting, The Tree of Life, Stoclet Frieze. This iconic painting later inspired the external facade of the "New Residence Hall" (also called the "Tree House"), a colorful 21-story student residence hall at Massachusetts College of Art and Design in Boston, Massachusetts.

Alex Proyas' 2009 film Knowing ends with the two young protagonists directed towards the tree of life.

The 2006 Darren Aronofsky film The Fountain features the Judeo-Christian tree of life as a major plot element in its non-linear narrative. In Central America during the Age of Discovery, it is the sought-after object of a Spanish conquistador, who believes its gift of eternal life will free Spain and its queen from the tyranny of a religious inquisition. In the present day, a sample from what is implied to be the same tree of life is used by a medical researcher—who seeks a cure for his ailing wife—to develop a serum that reverses the biological aging process. In the distant future, a space traveler (implied to be the same man from the present) uses the last vestiges of a tree's bark (again, implied to be the same tree of life) to keep himself alive as he journeys to Xibalba, a fictional dying star lying inside a nebula in the constellation Orion, which he believes will rejuvenate the tree—thereby granting him eternal life—when it explodes.

The 2021 adventure film Jungle Cruise follows a boat captain (Dwayne Johnson) who takes a scientist (Emily Blunt) on a quest to find the Tree.

Physical "trees of life"

  • In West Africa, the South Asian Moringa oleifera tree is regarded as a "tree of life" or "miracle tree" by some because it is arguably the most nutritious source of plant-derived food discovered on the planet. Modern scientists and some missionary groups have considered the plant as a possible solution for the treatment of severe malnutrition and aid for those with HIV/AIDS.

CS gas

From Wikipedia, the free encyclopedia
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The compound 2-chlorobenzalmalononitrile (also called o-chlorobenzylidene malononitrile; chemical formula: C10H5ClN2), a cyanocarbon, is the defining component of tear gas commonly referred to as CS gas, which is used as a riot control agent.

CS gas
Skeletal formula of CS gas
Space-filling model of CS gas
Names
Preferred IUPAC name
[(2-Chlorophenyl)methylidene]propanedinitrile
Other names
2-(2-Chlorobenzylidene)malononitrile
2-Chlorobenzalmalononitrile
o-Chlorobenzylidene malononitrile
OCBM
Tear gas
TL-238
EA-1779
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.018.435 Edit this at Wikidata
EC Number
  • 220-278-9
RTECS number
  • OO3675000
UNII
UN number 2810, 3276, 2811


Properties
C10H5ClN2
Molar mass 188.6 g/mol
Appearance White crystalline powder
Colourless gas when burned
Odor Pepper-like
Density 1.04 g/cm3
Melting point 93 °C (199 °F; 366 K)
Boiling point 310 °C (590 °F; 583 K)
Insoluble
Vapor pressure 3.4×10−5 mmHg at 20 °C
Hazards
GHS labelling:
GHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Danger
H302, H314, H330, H335, H372, H410
P260, P261, P264, P270, P271, P273, P280, P284, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P314, P320, P321, P330, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
2
1
0
Lethal dose or concentration (LD, LC):
  • 1806 mg/m3 (rat, 45 min)
  • 2753 mg/m3 (mouse, 20 min)
  • 1802 mg/m3 (rabbit, 10 min)
  • 2326 mg/m3 (guinea pig, 10 min)
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 0.05 ppm (0.4 mg/m3)
REL (Recommended)
C 0.05 ppm (0.4 mg/m3) [skin]
IDLH (Immediate danger)
2 mg/m3
Related compounds
Related compounds
SDBS

5-chloro-2-quinolinecarbonitrile
6-chloro-2-quinolinecarbonitrile
7-chloro-2-quinolinecarbonitrile

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Exposure causes a burning sensation and tearing of the eyes to the extent that the subject cannot keep their eyes open, and a burning irritation of the mucous membranes of the nose, mouth and throat, resulting in profuse coughing, nasal mucus discharge, disorientation, and difficulty breathing, partially incapacitating the subject. CS gas is an aerosol of a volatile solvent (a substance that dissolves other active substances and that easily evaporates) and 2-chlorobenzalmalononitrile, which is a solid compound at room temperature. CS gas is generally accepted as being non-lethal. It was first synthesized by two Americans, Ben Corson and Roger Stoughton, at Middlebury College in 1928, and the chemical's name is derived from the first letters of the scientists' surnames.

CS was developed and tested secretly at Porton Down in Wiltshire, UK, in the 1950s and 1960s. CS was used first on animals, then subsequently on British Army servicemen volunteers. CS has less effect on animals because they have different tear ducts and, in the case of non-human mammals, their fur inhibits the free entry of the gas.

Production

CS is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile via the Knoevenagel condensation:

Preparation of CS
ClC6H4CHO + H2C(CN)2 → ClC6H4CHC(CN)2 + H2O

The reaction is catalysed with a weak base like piperidine or pyridine. The production method has not changed since the substance was discovered by Corson and Stoughton. Other bases, solvent free methods and microwave promotion have been suggested to improve the production of the substance.

The physiological properties had been discovered already by the chemists first synthesising the compound in 1928: "Physiological Properties. Certain of these dinitriles have the effect of sneeze and tear gases. They are harmless when wet but to handle the dry powder is disastrous."

Use as an aerosol

As 2-chlorobenzalmalononitrile is a solid at room temperature, not a gas, a variety of techniques have been used to make this solid usable as an aerosol:

  • Melted and sprayed in the molten form.
  • Dissolved in organic solvent.
  • CS2 dry powder (CS2 is a siliconized, micro-pulverized form of CS).
  • CS from thermal grenades by generation of hot gases.

In the Waco Siege in the United States, CS was dissolved in the organic solvent dichloromethane (also known as methylene chloride). The solution was dispersed as an aerosol via explosive force and when the highly volatile dichloromethane evaporated, CS crystals precipitated and formed a fine dispersion in the air.

Effects

CS Gas used on 1 May 2013 in Istanbul
 
Tear gas shells used in Istanbul in 2013
 
CS gas shells used in Taksim Gezi Park, Istanbul, May 2013

Many types of tear gas and other riot control agents have been produced with effects ranging from mild tearing of the eyes to immediate vomiting and prostration. CN and CS are the most widely used and known, but around 15 different types of tear gas have been developed worldwide, e.g. adamsite or bromoacetone, CNB, and CNC. CS has become the most popular due to its strong effect. The effect of CS on a person will depend on whether it is packaged as a solution or used as an aerosol. The size of solution droplets and the size of the CS particulates after evaporation are factors determining its effect on the human body.

The chemical reacts with moisture on the skin and in the eyes, causing a burning sensation and the immediate forceful and uncontrollable shutting of the eyes. Effects usually include tears streaming from the eyes, profuse coughing, exceptional nasal discharge that is full of mucus, burning in the eyes, eyelids, nose and throat areas, disorientation, dizziness and restricted breathing. It will also burn the skin where sweaty or sunburned. In highly concentrated doses, it can also induce severe coughing and vomiting. Most of the immediate effects wear off within a few hours (such as exceptional nasal discharge and profuse coughing), although respiratory, gastrointestinal, and oral symptoms may persist for months. Excessive exposure can cause chemical burns resulting in permanent scarring.

Adults exposed to tear gas during the 2020 protests in Portland Oregon (USA) also reported menstrual changes (899; 54.5% of 1650 respondents who potentially menstruate). Exposure to tear gas is associated with avoidable healthcare utilization.

Secondary effects

People or objects contaminated with CS gas can cause secondary exposure to others, including healthcare professionals and police. In addition, repeated exposure may cause sensitisation.

Toxicity

TRPA1 (Transient Receptor Potential-Ankyrin 1) ion channel expressed on nociceptors (especially trigeminal) has been implicated as the site of action for CS gas in rodent models.

Although described as a non-lethal weapon for crowd control, studies have raised doubts about this classification. CS can cause severe pulmonary damage and can also significantly damage the heart and liver.

On 28 September 2000, Prof. Dr. Uwe Heinrich released a study commissioned by John C. Danforth, of the United States Office of Special Counsel, to investigate the use of CS by the FBI at the Branch Davidians' Mount Carmel compound. He said no human deaths had been reported, but concluded that the lethality of CS used would have been determined mainly by two factors: whether gas masks were used and whether the occupants were trapped in a room. He suggests that if no gas masks were used and the occupants were trapped, then, "there is a distinct possibility that this kind of CS exposure can significantly contribute to or even cause lethal effects".

CS gas can have a clastogenic effect (abnormal chromosome change) on mammalian cells, but no studies have linked it to miscarriages or stillbirths. In Egypt, CS gas was reported to be the cause of death of several protesters in Mohamed Mahmoud Street near Tahrir square during the November 2011 protests. The solvent in which CS is dissolved, methyl isobutyl ketone (MIBK), is classified as harmful by inhalation; irritating to the eyes and respiratory system; and repeated exposure may cause skin dryness or cracking.

Use

RWGŁ-3 Polish tear gas grenade launcher.
 
CS was used during attempts to flush the Viet Cong from their tunnels in the Vietnam War.

CS is used in spray form by many police forces as a temporary incapacitant and to subdue attackers, persons, or civil protestors. Officers who are trained in the use and application of CS spray are routinely exposed to it as part of their training.

Although predominantly used by police it has also been used in criminal attacks in various countries.

Use of CS in war is prohibited under the terms of the Chemical Weapons Convention, signed by most countries in 1993 with all but five other states signing between 1994 and 1997. The reasoning behind the prohibition is pragmatic: use of CS by one combatant could easily trigger retaliation with much more toxic chemical weapons such as nerve agents. Only five countries have not signed the Chemical Weapons Convention and are therefore unhindered by restrictions on the use of CS gas: Angola, Egypt, North Korea, Somalia, and South Sudan.

Domestic police use of CS is legal in many countries, as the Chemical Weapons Convention prohibits only military use.

Bahrain

Bahrain riot police use tear gas on protesters in Manama during 2011-2012 Bahraini uprising

CS gas was used extensively by Bahrain's police from the start of the Bahraini uprising. The Bahrain Independent Commission of Inquiry concluded that Bahrain's police used a disproportionate amount of CS gas when dispersing protests, and that in some situations, police fired CS gas into private homes in an "unnecessary and indiscriminate" manner. In one particular incident witnessed by Commission investigators, police fired "at least four tear gas canisters (each containing six projectiles) ... from a short range into the kitchen and living room of a home."

According to opposition activists and families of the dead, ten individuals died as a result of CS gas between 25 March 2011 and 17 December 2011. One allegedly died from the impact of the CS gas canister, and the remainder are said to have died from the effects of inhaling the gas. The Bahrain Independent Commission of Inquiry received information that a further three deaths may have been attributable to the use of CS gas. Of these three, one allegedly died from the impact of the canister, and two from the effects of inhaling the gas.

Canada

The Canadian Forces exposes basic training candidates to CS gas as part of gas mask training and drills. This training continues in subsequent career stages. Many law enforcement agencies also use CS gas as a riot control device. Since 2008, the SPVM police force in Montreal has increased its use of CS Gas for crowd control, although Police policy is to only use it as a last resort. Several incidents where protesters have been seriously injured by having CS gas fired at them from point-blank range have raised concerns about the methodology and training of Officers in the Montreal Riot Squad, particularly in relation to "Use of Force".

Chile

Tear gas is routinely used in Chile by Carabineros, to disrupt civilian protests. During the 2019 uprising the use of expired gas has been reported, prompting Carabineros to say that "they are like yogurt expired 5 days ago, it doesn’t damage people".

Peru

Peru Police forces spray CS gas in riot control situations.

Cyprus

CS was first tested in the field by the British army in Cyprus in 1958. At this time it was known by the code name T792.

Egypt

CS has been widely used by Egyptian Police/Military Forces from January 2011 onwards.

Hong Kong

The Police Tactical Unit of the Hong Kong Police Force used 87 rounds of CS projectiles (both riot gun launched and hand thrown) in Hong Kong on 28 September 2014 against thousands of protesters obstructing major thoroughfares in Hong Kong 2014 Hong Kong protests, also known as the Umbrella Movement.

The CS gas canisters and content used were purchased by the Hong Kong SAR Government from CHEMRING, a British weapons manufacturer. The crowd used umbrellas to fend off the gas, which was often ineffective. Apart from the HK police, CS gas spray is also used by Witness Protection and Firearms Section of Independent Commission Against Corruption (Hong Kong).

From 12 June to 4 August 2019, police used 1000 tear gas canisters. Then, on the single day of 5 August, police fired more than 800 tear gas canisters in their operations throughout almost every district of the city. In one instance, a tear gas canister was deployed indoors, in Kwai Fong station during a march, on 11 August 2019. The police initially denied the incident. In defense, protestors are seen picking up tear gas cans with thick gloves to throw them back or to extinguish them in sealed water containers.

Up to 22 October 2019, over 5000 made-in-China tear gas canisters have been deployed by the Hong Kong Police Force. Canisters marked with dates overdue have been collected in many occasions. It is unpredictable for the potential hazards to the Hong Kong environment and living conditions. Recent massive deaths of fish around Hong Kong seas was also suspected to be one of the consequences. Many birds were found dead in the Chinese University of Hong Kong, after 12 November that the riot police fired over 2000 tear gases towards the campus. A Hong Kong journalist, Chan Yu-hong from the Stand News declared he was diagnosed with chloracne (by a Traditional Chinese physician instead of a physician) after exposure to made-in-China tear gas while covering the 2019 Hong Kong protests.

The overuse of tear gas has been one of the concerns in the anti-extradition bill protests.

Iraq

Iraq successfully developed CS during the 1970s and during the 1980s produced tons of the substance firstly at Salman Pak and later at al-Muthanna.

Blackwater Worldwide, acting as an agent of the United States, deployed CS in the Iraq War from a helicopter hovering over a checkpoint in the Green Zone in Baghdad.

Israel

Israel Police forces spray CS gas in riot control situations. It is widely used at demonstrations within the Palestinian Territories and at the Israeli West Bank barrier.

Philippines

CS tear gas was used in suppression of the mutiny in Makati that was led by Sen. Antonio Trillanes. The tear gas was fired in the building and all the people in the building including reporters were affected.

Romania

The Gendarmerie of Bucharest used large quantities of CS gas against civilians during the protests of 10 August 2018 in Bucharest.

Spain

Tear gas is not commonly used in Spain but it has been used some times to disrupt civilian protests by the Policia Nacional and Mossos d'Esquadra in Catalonia.

Sri Lanka

The LTTE, also known as Tamil Tigers of Sri Lanka, an insurgent group in Sri Lanka used CS gas against government forces in September 2008. Its use hindered the army's progress but ultimately proved ineffective in preventing the army from overrunning LTTE positions.

This is one of the few cases of insurgents using CS gas.

Sudan

Sudanese forces extensively used CS gas during the latest wave of demonstrations began in 2018. The use of CS gas fired through rifles or hand grenades is not exclusive to police forces but is widely used by non-trained militia to suppress protesters movement and to intimidate civilians by firing blindly into neighborhoods and homes. CS gas cannisters are generally used also as a ballistic weapon and aimed at the faces of protesters to cause serious body and head injuries. Some death cases were recorded due to choking on tear gas because of excessive use in confined areas.

United Kingdom

Northern Ireland

CS gas was used extensively in the Bogside area of Derry, Northern Ireland during the "Battle of the Bogside", a two-day riot in August 1969. A total of 1,091 canisters containing 12.5g of CS each, and 14 canisters containing 50 g of CS each, were released in the densely populated residential area. On 30 August the Himsworth Inquiry was set up to investigate the medical effects of its use in Derry. Its conclusions, viewed in the political context of the time, still pointed towards the necessity of further testing of CS gas before being used as a riot control agent. During the rioting in Belfast, the following year, known as the Falls Curfew, the Army fired up to 1,600 canisters into the densely populated Falls Road area. It was also used in Lenadoon on 9 July 1972 on the breakdown of the IRA ceasefire. Not long after, the British Army and Royal Ulster Constabulary ceased using CS in Northern Ireland.

Great Britain

CS gas

CS gas has not been routinely deployed on the British mainland. It has seen use in rare cases. The first use of CS gas on the UK mainland that was not part of military training was carried out in 1944 during a hostage siege at a north London address. Soldiers were asked to throw CS grenades through the skylight in hope of bringing the incident to a speedy conclusion, but the hostage-taker had brought his civilian-issue gas mask with him, negating the effect. The siege of Trough Gate 1973 in Oldham was the second non-military use of CS gas on the UK mainland. During a four-hour standoff, Frank Alan Stockton shot at police but was flushed from his home with CS gas and police dogs.

During the 1980 assault on the Iranian Embassy, SAS soldiers used CS gas contained within stun grenades to incapacitate the militants who had kept the building under siege for six days. All but one of the remaining hostages were saved and all but one of the hostage-takers were killed, with the other being taken into custody.

In 1981, CS gas was used to quell rioting in the Toxteth area of Liverpool.

Following the 2011 England riots, there was consideration given to making CS gas, water cannon and other riot control measures available to police for use in the event of serious disorder. The British Armed Forces use CS gas annually to test their chemical, biological, radiological and nuclear defense (CBRN) equipment. During initial training they introduce recruits to CS gas by placing them in a small enclosed space known as a Confidence Test Facility (CTF) and igniting chemical tablets to induce CS production. After recruits have carried out their CBRN drills, they must remove their respirators so that they are exposed to the CS for up to 20 seconds to experience its effects and become confident their respirators work.

CS spray

CS incapacitant spray had been used routinely by the British police since its introduction in 1996. It was issued as an item of equipment to police officers for protection and to assist in dealing with violent incidents. British police recruits are typically exposed to CS aerosol, in a controlled environment, as part of their basic training. A six-month trial by sixteen police forces in England began on 1 March 1996. CS spray was used in the UK more than 10,000 times in the period between its introduction in 1996 and September 1998. Forces began replacing CS spray with Captor or PAVA spray, due to its non-flammable nature. This allowed use in conjunction with Tasers, which have been rolled out more widely. As a result, CS spray is now redundant – with Captor or PAVA used by all forces.

The CS spray used by police forces was in the form of a hand-held aerosol canister containing a 5% solution of CS dissolved in methyl isobutyl ketone and propelled by pressurized nitrogen. The CS spray used by UK police was generally more concentrated than that used by American police forces (5% vs 1%). The liquid stream is directed where the user points the canister, being accurate up to 4 metres. Police are also trained in helping the incapacitated person recover once successfully restrained. Under Section 5 of the Firearms Act, CS and other incapacitant sprays are classed as prohibited weapons, making it unlawful for a member of the public to possess them.

On 16 March 1996, a Gambian asylum seeker, Ibrahima Sey, was taken to Ilford Police Station in east London. Whilst incapacitating Sey, who was suffering from excited delirium, police sprayed him with CS spray and held him on the ground for approximately 15 minutes, and he subsequently died. In 1999, the mental health charity MIND called for a suspension of the use of CS spray on mentally ill people until it was proved to be safe. In February 2006, Dan Ford, from Wareham in Dorset, received permanent scarring to his face after being sprayed with CS during an arrest by police. Ford was subsequently advised by doctors to stay out of sunlight for at least 12 months. After the incident, his cousin, Donna Lewis, was quoted as saying, "To look at him, it was like looking at a melting man, with liquid oozing from his face."

United States

40mm CS gas canister used during the 2020 George Floyd protests in Portland, Oregon

CS is used by many police forces within the United States. It was used by Federal Bureau of Investigation law enforcement officials in the 1993 Waco Siege. Riot police in Pittsburgh, Pennsylvania in September 2009 used CS gas and riot control techniques to disperse assemblies in the vicinity of the 2009 G-20 Pittsburgh summit. Tear gas was used in at least 100 cities during the 2020 protests that took place in the U.S. In Portland, Oregon alone, tear gas was used more than 100 times in a two-week period and there were at least two nights in which it was used more than twenty times.

In Berkeley, California during the Bloody Thursday events in the People's Park on 21 May 1969, a midday memorial was held for student James Rector, a non-protester shot and killed by police, at Sproul Plaza on the university campus. In his honor, several thousand people peacefully assembled to listen to speakers remembering his life. National Guard troops surrounded Sproul Plaza, donned their gas masks, and pointed their bayonets inward, while helicopters dropped CS gas directly on the trapped crowd. No escape was possible, and the gas caused acute respiratory distress, disorientation, temporary blindness and vomiting. Many people, including children and the elderly, were injured during the ensuing panic. The gas was so intense that breezes carried it into Cowell Memorial Hospital, endangering patients, interrupting operations and incapacitating nurses. Students at nearby Jefferson and Franklin elementary schools were also affected.

Members of the United States armed forces are exposed to CS during initial training, and during training refresher courses or equipment maintenance exercises, using CS tablets that are melted on a hotplate. This is to demonstrate the importance of properly wearing a military gas mask or protective mask, as the agent's presence quickly reveals an improper fit or seal of the mask's rubber gaskets against the face. Following exposure while wearing a mask, recruits are ordered to remove the masks and endure exposure in the room. These exercises also encourage confidence in the ability of the equipment to protect the wearer from such chemical attacks. Such an event is a requirement for graduation from United States Army Basic Training, Air Force Basic Military Training, Navy Basic Training, and Marine Corps recruit training. CS gas in the form of grenades is also used extensively in the United States Marine Corps and United States Army in some service schools. CS gas is used during the final field exercise of the Scout Sniper Basic Course to simulate being compromised. In addition, it is used during the 25 km (16 mi) escape-and-evasion exercise ("Trail of Tears"), the last event before graduation from the course. Navy Corpsmen participating in Field Medic training in order to serve with the Marines must go through their second CS gas exercise before finally arriving at their unit. It is also used during several events in the Marine Corps Basic Reconnaissance Course (BRC) including some rucksack runs and escape-and-evasion exercises. While students going through the course are given the opportunity to bring and wear a gas mask for the event, usually none are worn because once donned, gas masks could not be removed until the end of the exercise. This could last anywhere from 3–12 hours and would make running 25 km (15 miles) while wearing 125 lb (57 kg) of gear virtually impossible.

Vietnam

It has been reported that thousands of tons of CS gas were used by the U.S. forces in Vietnam to bring Viet Cong into the open. It was also used by the North Vietnamese forces in some battles like Hue in 1968 or during the Easter Offensive in 1972.

Elsewhere

CS gas has been and is still routinely used by Greek riot police (MAT) in order to quell student and labour protests, as well as riots.

CS was used to quell a protest in Lusaka, Zambia in July 1997 and the 1999 WTO riots in Seattle. Amnesty International reported that it had been manufactured by the UK company Pains-Wessex. Subsequently, Amnesty called for an export ban when the receiving regime is either not fully trained in the use of CS, or had shown usage "contrary to the manufacturer’s instructions".

In September 2000, the Guardian newspaper revealed how a UK company, HPP, used legal loopholes to export CS to a private security company in Rwanda, in breach of United Nations sanctions. The Guardian also reported that CS was used by the Hutu militia in Rwanda to flush Tutsis out of buildings before hacking them to death.

CS has been used by the government in South Africa; by Israel against Palestinians and Israelis; by the South Korean government in Seoul, and during the Balkan conflicts by Serbia. In Malta it was used by police between 1981 and 1987 to the detriment of Nationalist Party Supporters.

CS tear gas was used at the G8 protests in Genoa, Italy and Quebec City, Canada during the FTAA anti-globalization demonstrations during the Quebec City Summit of the Americas.

The Malaysia Federal Reserve Unit has also been known to use CS tear gas against its citizens who rallied for clean and fair elections under what were called Bersih rallies in 2011 and 2012.

The Canadian, Norwegian, Dutch, and Australian Defence Forces train their personnel with CS gas in a manner similar to that of the US, as it is a basic part of CBRN (Chemical, Biological, Radiological, Nuclear) training. Gas is released by burning tablets, usually in a building reserved for this purpose (a "gas hut"). In the training, the person enters the building unprotected and must fit and clear the gas mask before leaving. Other drills such as drinking and under-mask decontamination are also practiced. Some Norwegian units are exposed to CS gas while engaged in mental and physical activity such as addressing the officer in command by stating name, rank, and troop before doing 30 push-ups.

In Australia, prison officers used CS gas against five teenage boys in Darwin's Don Dale Juvenile Detention Centre in August 2014.

Operator (computer programming)

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