GHS hazard categories for anhydrous ammonia

OP, what is GHS? I believe many people, just like me, don’t know, so I’ll explain it here. Learn and apply immediately: An introduction to GHS. Using chemicals to enhance and improve life is the trend in today’s world. While these products bring benefits, they may also have negative effects on human health or the environment. Therefore, over the years many **or organizations have enacted various laws or regulations requiring that information be conveyed to users of relevant chemicals through labels or Safety Data Sheets. Given the large quantity and variety of chemicals, individual regulations for any single entity cannot effectively manage all of them. The provision of information enables users of these chemicals to have a comprehensive understanding, allowing them to take appropriate protective measures when using them individually. Most of the current relevant regulations are similar, but differences in content across different **can result in the same chemical having different labels or Safety Data Sheets. Due to different definitions of hazards, for example, a certain chemical may be considered flammable in one context **but not flammable in another**. Or for example, if it is classified as a carcinogen in one country, it may not be classified as such in another. Therefore, countries around the world also differ in regards to when or how to communicate hazard information through labels or Safety Data Sheets. Therefore, companies involved in international trade must have a large number of experienced experts to meet these various regulatory requirements and prepare different labels and Safety Data Sheets. In addition, establishing and maintaining a comprehensible system for classifying and labeling chemicals is a complex task. Given the global trade in chemicals, the scope of regulations aimed at ensuring safety in their use, transportation, and disposal is very broad. Therefore, it is recognized that adopting internationally harmonized approaches to classification and labeling can provide a foundation for such schemes. Once countries have consistent and accurate information on the production or import of chemicals within their own borders, they can establish infrastructure to control chemical exposure as well as protect human health and the environment. The development history of GHS: 1. International organizations began work on the classification and labeling of chemicals as early as the early 1950s. In 1952, the International Labour Organization (ILO) began to understand and study the classification and labeling of hazardous substances. 2. In 1953, the United Nations Economic and Social Council (ECOSOC) established the Economic Commission for Europe, and a group of United Nations experts began to oversee the transport of dangerous goods (UNCETDG). The committee carefully developed the first internationally recognized system for the classification and labeling of chemicals, intended for the transport of hazardous materials. 3. In 1956, the first edition of the United Nations Recommendations on the Transport of Dangerous Goods (Orange Book) was published. United Nations organizations such as the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO), as well as other entities (organizations or companies) in the international or domestic transport sector, use this recommendation as a basis for the classification and labeling of chemicals for transport purposes. This recommendation is now adopted by most United Nations Member States in their transport legislation, and it is also used by many developing countries as a guideline for the classification and labeling of chemicals in the workplace. 4. In 1989, the International Labour Organization adopted a resolution regarding the classification and labeling of hazardous chemicals used in the workplace, and in 1990 it issued safety protocols and recommendations concerning the use of chemicals in workplaces. 5. To reduce physical hazards to workers and consumers as well as environmental pollution, and to lessen barriers to cross-border trade, the United Nations Conference on Environment and Development (UNCED) and the International Forum on Chemical Safety (IFCS) adopted a resolution in 1992 recommending that countries carry out international harmonization of chemical classification and labeling. UNCED and IFCS adopted a resolution in 1992 recommending that countries carry out international coordination on the classification and labeling of chemicals, in order to reduce the risks posed by chemicals to human health and the environment, as well as to cut down the costs associated with complying with varying labeling requirements in different countries in the context of international trade in chemicals. Therefore, GHS for the classification and labeling of chemicals was developed jointly by the ILO, OECD, and UNCETDG, with the following division of responsibilities: (1) OECD: responsible for establishing criteria for classifying the hazards of chemicals to human health and the environment ； (2) UNCETDG: Responsible for establishing safety standards for the physical properties of chemicals ； (3) ILO: Developing standards based on the first two entities, and responsible for creating relevant labeling and classification methods. 6. Upon completion of the work in 2001, it was transferred to the newly established Subcommittee of Experts on the Globally Harmonized System of Classification and Labelling of Chemicals (UNSCEGHS), created by the United Nations Economic and Social Council in its resolution 1995/65 of 26 October 1999 as a subsidiary body of the former Committee of Experts on the Transport of Dangerous Goods, which was simultaneously renamed the Committee of Experts on the Transport of Dangerous Goods and on the Globally Harmonized System of Classification and Labelling of Chemicals (UNSCETDG/GHS). The committee and its subcommittees carried out two years of preparatory work, with their first task being to make the global harmonization system available for use and application worldwide. Currently, the Global Harmonized System for the classification and labeling of chemicals is being developed jointly by the International Labour Organization (ILO), the Organization for Economic Co-operation and Development (OECD), and the United Nations Committee of Experts on the Transport of Dangerous Goods (UNCETDG). 7. Paragraph 22(c) of the Plan of Action adopted in Johannesburg on September 4, 2002, the United Nations World Summit on Sustainable Development encouraged countries to implement the new Globally Harmonized System as soon as possible, aiming for its full implementation by 2008. Chemical management, which is being widely implemented across countries around the world, will lead to a safer environment for the global public, while still allowing for the convenient use of chemicals. By promoting international trade, the classification and labeling of chemical hazards that companies must comply with have become more consistent, and such coordination will also facilitate international trade. In December 2002, the United Nations Expert Committee on the Transport of Dangerous Goods and on the Globally Harmonized System of Classification and Labelling of Chemicals (UNCETDG/GHS) completed the development of the GHS system. In July 2003, the GHS was officially adopted by the United Nations Economic and Social Council, which authorized its translation into the official languages of the United Nations for use worldwide. 8. In 2005, the already published GHS was revised, and the first revised version was published.

Hazard overview: Hazard category: Class 2.3 – Toxic gases. Routes of exposure: Inhalation. Health hazards: Low concentrations of ammonia irritate the mucous membranes, while high concentrations can cause tissue dissolution and necrosis. Acute poisoning: In mild cases, symptoms such as tearing, sore throat, hoarseness, coughing, and phlegm production occur ； Congestion and edema of the conjunctiva, nasal mucosa, and pharynx ； The chest X-ray findings are consistent with bronchitis or peribronchitis. In moderate poisoning, the aforementioned symptoms worsen, with difficulty breathing and cyanosis occurring ； The chest X-ray findings are consistent with pneumonia or interstitial pneumonia. In severe cases, toxic pulmonary edema may occur, or respiratory distress syndrome can develop; patients experience severe coughing, the production of large amounts of pink frothy sputum, respiratory distress, delirium, coma, shock, and other symptoms. Laryngeal edema or necrosis and detachment of the bronchial mucosa can occur, leading to asphyxiation. High concentrations of ammonia can cause reflexive respiratory arrest. Liquid ammonia or high-concentration ammonia can cause eye burns ； Liquid ammonia can cause skin burns. Environmental hazards: It causes severe damage to the environment, polluting water bodies, soil, and the atmosphere. Fire and explosion hazard: This product is flammable, toxic, and irritating. First aid measures: Skin contact: Immediately remove contaminated clothing and rinse thoroughly with 2% boric acid solution or plenty of water. Seek medical attention. Eye contact: Immediately lift the eyelids and rinse thoroughly with plenty of flowing water or saline for at least 15 minutes. Seek medical attention. Inhalation: Quickly move to a place with fresh air. Keep the airways clear. If there is difficulty breathing, administer oxygen. If breathing stops, perform artificial respiration immediately. Seek medical attention. Ingestion: Preventive measures. Hazardous properties: Can form explosive mixtures when mixed with air. It can catch fire and explode in the presence of open flames or high heat. It undergoes violent chemical reactions upon contact with fluorine, chlorine, and the like. In the event of high temperatures, the pressure inside the container increases, posing a risk of cracking and explosion. Harmful combustion products: nitrogen oxides, ammonia. Fire extinguishing method: Firefighters must wear full-body fire and poison-resistant suits and extinguish the fire from the upwind direction. Cut off the gas supply. If the gas supply cannot be cut off, it is not allowed to extinguish the flame at the leak site. **Cool the container; if possible, move it away from the fire to an open area. Extinguishing agents: fog water, alcohol-resistant foam, carbon dioxide, sand. Emergency response to leaks: Evacuate people from the area affected by the leak to an area upwind immediately, isolate the zone over a 150-m radius, and strictly restrict access. Cut off the source of fire. It is recommended that emergency responders wear self-contained positive-pressure breathing apparatus and anti-static work clothing. Seal the source of the leak as much as possible. Ensure proper ventilation to accelerate diffusion. In areas with high concentration leaks, mist containing hydrochloric acid is sprayed to neutralize, dilute, and dissolve them. Construct dikes or dig pits to contain the large amount of wastewater generated. If possible, use an exhaust fan to send the residual gas or leaking gas to a scrubber tower or a fume hood connected to the tower. It is advisable to install dilute acid spraying facilities in the tank area. Leaking containers must be properly handled, repaired, and inspected before being used again. Handling and Storage: Handling precautions: Maintain strict closure, and provide adequate local exhaust ventilation as well as general ventilation. Operators must receive specialized training and strictly adhere to operating procedures. It is recommended that operators wear filter-type gas masks (half-masks), chemical safety goggles, anti-static work clothing, and rubber gloves. Stay away from flames and heat sources; smoking is strictly prohibited in the workplace. Use explosion-proof ventilation systems and equipment. Prevent gas from leaking into the workplace air. Avoid contact with oxidizers, acids, and halogens. Handle with care during transportation to prevent damage to the cylinders and accessories. Equipped with fire-fighting equipment of appropriate types and quantities, as well as emergency response equipment for leaks. Storage precautions: Store in a cool, well-ventilated warehouse. Keep away from flames and heat sources. The storage temperature should not exceed 30°C. It should be stored separately from oxidizers, acids, halogens, and food chemicals; mixed storage is strictly prohibited. Use explosion-proof lighting and ventilation facilities. The use of mechanical equipment and tools that can generate sparks is prohibited. The storage area should be equipped with emergency equipment for handling leaks. Contact control/Personal protection: Occupational exposure limit: MAC (mg/m3): -- TWA (mg/m3): 20 STEL (mg/m3): 30 Engineering controls: Strictly maintain closure, and provide adequate local exhaust ventilation as well as general ventilation. Provide safety showers and eye wash stations. Respiratory protection: When the concentration in the air is above the safe level, it is recommended to wear a filtering gas mask (half-mask). An air respirator must be worn during emergency rescue or evacuation. Eye protection: Wear chemical safety goggles. Body protection: Wear anti-static work clothes. Hand protection: Wear rubber gloves. Other protections: Smoking, eating, and drinking are prohibited at the work site. Work is done, take a shower**. Maintain good hygiene* habits. Physical and chemical properties: Appearance and characteristics: A colorless gas with a pungent, irritating odor. Molecular formula: NH3 Molecular weight: 17.03 pH value: Not applicable Melting point (°C): -77.7 Relative density (water): 0.82 (-79°C) Boiling point (°C): -33.5 Relative vapor density (air): 0.6 Ignition temperature (°C): 651 Upper explosion limit: 27.4 Lower explosion limit: 15.7 Critical temperature (°C): 132.5 Critical pressure (MPa): 11.40 Solubility: Highly soluble in water, ethanol, and ether. Primary uses: used as a refrigerant and in the production of ammonium salts and nitrogen fertilizers. Stability and Reactivity Stability: Stable Incompatible substances: Halogens, acyl chlorides, acids, chloroform, strong oxidizing agents. Conditions to avoid contact: Polymerization hazard: Does not polymerize. Decomposition products: Toxicological data. Acute toxicity: LD50: 350 mg/kg (oral, rats); LC50: 1390 mg/m3, 4 hours (inhalation, rats). Irritation: In rabbits, when applied to the eyes: 100 mg causes severe irritation. Other harmful effects: This substance poses serious threats to the environment; special attention should be paid to its contamination of surface water, soil, air, and drinking water. Waste Disposal: Nature of the waste: Method of waste disposal: First dilute with water, then neutralize with hydrochloric acid, and subsequently discharge into the wastewater system. Disposal precautions: Transport information. Hazardous goods code: 23003. UN number: 1005. Packaging mark: Toxic gas

The Global System of Classification and Labelling of Chemicals (GHS) was revised for the second time in 2007! Download address: http://www.unece.org/trans/danger/publi/ghs/ghs_rev02/02files_c.html