Welcome to the Portland State University ECOPOL website
ECOPOL ONGOING MISSION...
The Portland State University EcoPol project looks at the intersection between ecological and economical topics with the goal of changing readers thoughts, behaviors and actions. Four times a year a separate website is developed and launched in support of a particular topic, and the main goal is this - how can we encourage people to take action to make policy change which improves sustainability?
This site addresses progressive leather tanning for a cleaner environment.
Explore more about ECOPOL through our blog:
http://ecopolproject.blogspot.com
THE LEATHER PRODUCTION PROCESS
While leather production is going to vary slightly from factory to factory, here is a basic break-down of the production process:
The leather making process begins with carefully removing the hide from the flesh of the animal. The hides are then stored in temperature-controlled cool rooms and preserved in salt, and once ready for processing, are sorted by quality and weight. The next step is to soak the hides in large drums so as to remove any remaining dirt, salt, or other materials.
While leather production is going to vary slightly from factory to factory, here is a basic break-down of the production process:
The leather making process begins with carefully removing the hide from the flesh of the animal. The hides are then stored in temperature-controlled cool rooms and preserved in salt, and once ready for processing, are sorted by quality and weight. The next step is to soak the hides in large drums so as to remove any remaining dirt, salt, or other materials.
Large drum. Photo credit: Wikipedia
Once cleaned, hides are put through the process of de-fleshing and liming. The skins are run through a mechanical fleshing machine that acts as a mounted knife and takes any existing flesh or fat remnants off the inside of the skin. Next, the hair is chemically removed from the hide by a calcium carbonate (lime) bath.
Once hair is removed, the hide is prepared for tanning by being treated with acid and salt in order to remove unnecessary proteins and interfiber substances. This is known as bating, and it allows the skin fibers to absorb tanning agents during the tanning process.
The most common method of tanning is chromium-tanning, practiced about 90% of the time worldwide. Chromium-tanning is accomplished by putting the hides in large, rotating drums of water, and then adding the proper amount of chromium salt (a green powder). Continuous agitation of the hides allows for the tanning agent to be evenly distributed. When the tanning process is finished, the hides can officially be called leather. The leather, now the color blue (characteristic of chrome-tanned leather), is taken out of the drums and hung to drain.
Once hair is removed, the hide is prepared for tanning by being treated with acid and salt in order to remove unnecessary proteins and interfiber substances. This is known as bating, and it allows the skin fibers to absorb tanning agents during the tanning process.
The most common method of tanning is chromium-tanning, practiced about 90% of the time worldwide. Chromium-tanning is accomplished by putting the hides in large, rotating drums of water, and then adding the proper amount of chromium salt (a green powder). Continuous agitation of the hides allows for the tanning agent to be evenly distributed. When the tanning process is finished, the hides can officially be called leather. The leather, now the color blue (characteristic of chrome-tanned leather), is taken out of the drums and hung to drain.
Chrome-tanned leather. Photo credit: Wikipedia
In order to remove any excess water, the leather is put through large rollers, called samming, and then put through more rollers that shave the leather down to a specified thickness. This ensures that the leather is even in thickness throughout.
Next, the leather is put back into the rotating drums to be dyed and “fat-liquored”, natural and/or synthetic oils used to replace the natural greases removed from the hides during the previous processes. Fat-liquoring ensures that the leather fibers will be lubricated once dried. After drying, the leather is mechanically staked in order to soften it and make it suppler. The leather is then ready to be finished.
Next, the leather is put back into the rotating drums to be dyed and “fat-liquored”, natural and/or synthetic oils used to replace the natural greases removed from the hides during the previous processes. Fat-liquoring ensures that the leather fibers will be lubricated once dried. After drying, the leather is mechanically staked in order to soften it and make it suppler. The leather is then ready to be finished.
Drying leather. Photo credit: The World Effect
The final step is called finishing; this is where the leather is given its final surface treatment. This includes coloring, embossing, waxing, ironing, etc.; all of the processes done to give leather the desired appearance and feel. Once finished, the leather is ready for purchase.
Finished leather. Photo credit: Leather Farid
REFERENCES:
http://www.euroleather.com/process.htm
http://www.pergamena.net/products-services/how-we-make-leather
http://www.euroleather.com/process.htm
http://www.pergamena.net/products-services/how-we-make-leather
THE HAZARDS OF LEATHER PRODUCTION
When the average U.S. citizen hears the word “leather”, they probably think about nice jackets, shoes, purses, etc. Little thought would be specifically given to the leather itself or how it goes from being the raw hide of an animal to a finished product. Fur and animal hide have come to symbolize luxury and status. Leather is not needed in such mass quantities just for the purpose of luxury. According to Ecouterre, a website devoted to the future of sustainable fashion design, “across the board there is no way to defend leather production as eco-friendly or sustainable.” Most people don’t realize the hazards associated with the leather industry and the impact it has on humans and the environment.
The chemicals used to turn animal skin into leather, including various aldehydes, coal-tar derivatives, arsenic, and cyanide-based finishes to name a few, are very dangerous and have been linked to various types of cancer. The National Institute of Health has an occupational health database that lists hazardous chemicals associated with specific occupations, and under “Leather Tanning and Processing”, 246 chemicals were listed as hazardous agents (Haz-Map).
Groundwater samples collected near tanneries have shown the presence of arsenic, chromium, lead, and zinc. Furthermore, tanneries have also been known to emit toxic gases like ammonia, hydrogen sulfide, and carcinogenic arylamines into the air (Ecouterre).
When the average U.S. citizen hears the word “leather”, they probably think about nice jackets, shoes, purses, etc. Little thought would be specifically given to the leather itself or how it goes from being the raw hide of an animal to a finished product. Fur and animal hide have come to symbolize luxury and status. Leather is not needed in such mass quantities just for the purpose of luxury. According to Ecouterre, a website devoted to the future of sustainable fashion design, “across the board there is no way to defend leather production as eco-friendly or sustainable.” Most people don’t realize the hazards associated with the leather industry and the impact it has on humans and the environment.
The chemicals used to turn animal skin into leather, including various aldehydes, coal-tar derivatives, arsenic, and cyanide-based finishes to name a few, are very dangerous and have been linked to various types of cancer. The National Institute of Health has an occupational health database that lists hazardous chemicals associated with specific occupations, and under “Leather Tanning and Processing”, 246 chemicals were listed as hazardous agents (Haz-Map).
Groundwater samples collected near tanneries have shown the presence of arsenic, chromium, lead, and zinc. Furthermore, tanneries have also been known to emit toxic gases like ammonia, hydrogen sulfide, and carcinogenic arylamines into the air (Ecouterre).
Photo credit: Worst Polluted
Chromium is used in about 90% (estimates range to over 95%) of leather tanning operations worldwide, and its use has long been a concern in regards to its potential environmental impact. Trivalent chromium, the form most commonly used in tanning, is naturally occurring and essential for good health. Under certain conditions, however, trivalent chromium will oxidize and turn into hexavalent chromium. Hexavalent chromium is carcinogenic and can pose severe health concerns for humans, animals, and the environment (Wisconsin Department of Health Services).
Chromium powder. Photo credit: made-in-china.com
While there are other methods of tanning, such as vegetable tanning, chromium is used most of all because it produces leather that is softer and suppler than the other methods, and doesn’t discolor or lose its shape as much in water. Chromium-tanned hides also pick up more color during the dying process (Moore & Giles).
Even though vegetable-tanning sounds more eco-friendly, and is often touted as being less harmful to the environment, Bill Bartholomew, a representative for The Leather Group, recently admitted that eco-friendly vegetable-tanning is just as polluting as chrome-tanning (Ecouterre).
Acute effects of hexavalent chromium exposure include irritation to the mouth, throat, lungs, and nose (if inhaled); skin irritation and allergic reactions (if the skin was exposed); and digestive problems, kidney damage, or liver damage (if consumed contaminated food or water). Long-term effects of chromium exposure include lung cancer, lung irritation resulting in asthma, liver or kidney damage, impaired immune system, and reproductive problems (Wisconsin Department of Health Services).
While many tanneries have strict regulations for purifying water used during the tanning process as much as possible of residues and pollutants, the majority of the tanning industry operates from developing countries where regulations are minimal or nonexistent. Tanneries are so toxic, that 95% of U.S. tanneries have moved their operations overseas to avoid environmental and health regulations (Organic Leather).
India is a prime example of a country with minimal regulations. The Ecologist reports that a 2005 study showed 69,000 tons of chrome salts being used annually in 1,600 Indian tanneries, yet workers are not provided with proper safety equipment or protective gear regardless of the dangers.
Even though vegetable-tanning sounds more eco-friendly, and is often touted as being less harmful to the environment, Bill Bartholomew, a representative for The Leather Group, recently admitted that eco-friendly vegetable-tanning is just as polluting as chrome-tanning (Ecouterre).
Acute effects of hexavalent chromium exposure include irritation to the mouth, throat, lungs, and nose (if inhaled); skin irritation and allergic reactions (if the skin was exposed); and digestive problems, kidney damage, or liver damage (if consumed contaminated food or water). Long-term effects of chromium exposure include lung cancer, lung irritation resulting in asthma, liver or kidney damage, impaired immune system, and reproductive problems (Wisconsin Department of Health Services).
While many tanneries have strict regulations for purifying water used during the tanning process as much as possible of residues and pollutants, the majority of the tanning industry operates from developing countries where regulations are minimal or nonexistent. Tanneries are so toxic, that 95% of U.S. tanneries have moved their operations overseas to avoid environmental and health regulations (Organic Leather).
India is a prime example of a country with minimal regulations. The Ecologist reports that a 2005 study showed 69,000 tons of chrome salts being used annually in 1,600 Indian tanneries, yet workers are not provided with proper safety equipment or protective gear regardless of the dangers.
In the Hazaribagh neighborhood of Dhaka, Bangladesh, tanneries are packed together, side by side. While 90% of leather and leather goods produced in Bangladesh come from this very neighborhood, not a single one of the tanneries treats its wastewater. The water, which contains animal flesh, sulfuric acid, chromium, and lead, spews out onto the soil and into open gutters, eventually entering the region’s main river and central water supply. The toxic waste Richard Pearshouse, author of the Human Rights Watch report, said that “Hazaribagh’s tanneries flood the environment with harmful chemicals,” and that “local residents fall sick and workers suffer daily from their exposure to harmful tannery chemicals.” During his five months of research in Dhaka, Pearshouse noted that the air and soil were incredibly contaminated in Hazaribagh, and that he even saw some residents bathing in ponds that were black with pollution (Reuters).
Photo credit: Worst Polluted
[For more information on the hazardous effects of leather tanneries in the Hazaribagh neighborhood of Dhaka, Bangladesh, visit Ecouterre and TIME.]
As you can see from the chart below, the regions most impacted by chromium pollution from tannery operations are South Asia, Central America, South America, and Africa, with the country of Bangladesh being an obvious hot-spot for chromium pollution.
As you can see from the chart below, the regions most impacted by chromium pollution from tannery operations are South Asia, Central America, South America, and Africa, with the country of Bangladesh being an obvious hot-spot for chromium pollution.
2011 - Population estimates are preliminary and are based on an ongoing global assessment of known polluted sites.
Photo credit: Worst Polluted
Stories like these don’t take place only in developing countries; they also happen right here in the United States. The Centers for Disease Control and Prevention found that leukemia incidence among residents near a Kentucky tannery were five times the national average (PETA).
In Gloversville, New York, the former Demis Leather tannery poses a threat to the public health and welfare. Despite the fact that the tannery is no longer operable, Environmental Protection Agency officials report that hazardous substances, pollutants, and contaminants are still present at the site and that humans can potentially be exposed via inhalation, ingestion, and/or direct human contact. These contaminants, labeled “typical leather industry chemicals,” even pose a threat of fire or explosion (The Leader-Herald).
In Gloversville, New York, the former Demis Leather tannery poses a threat to the public health and welfare. Despite the fact that the tannery is no longer operable, Environmental Protection Agency officials report that hazardous substances, pollutants, and contaminants are still present at the site and that humans can potentially be exposed via inhalation, ingestion, and/or direct human contact. These contaminants, labeled “typical leather industry chemicals,” even pose a threat of fire or explosion (The Leader-Herald).
Demis Leather tannery in New York. Photo credit: The Leader-Herald
WHAT WOULD HAPPEN IF THE LEATHER INDUSTRY STOPPED
Globally speaking, the leather industry’s revenue is forecast to reach $91.2 billion by 2018 (Research and Markets). Unfortunately, this is a growing industry with many players competing to gain market share. While it would seem that bringing leather production to a standstill would be the most logical solution when considering all the harmful effects it has on humans and the environment, putting an end to the leather industry would be devastating for the thousands of families around the world who have become dependent on leather production as their main source of income.
Globally speaking, the leather industry’s revenue is forecast to reach $91.2 billion by 2018 (Research and Markets). Unfortunately, this is a growing industry with many players competing to gain market share. While it would seem that bringing leather production to a standstill would be the most logical solution when considering all the harmful effects it has on humans and the environment, putting an end to the leather industry would be devastating for the thousands of families around the world who have become dependent on leather production as their main source of income.
Tannery worker in Bangladesh. Photo credit: TIME
Tannery workers in developing countries are often forced to endure horrible and unsafe working conditions in order to get by and support their families. Wages are incredibly low; some make as little as 50 cents a day. It’s not uncommon to see children as young as seven years old working in the tanneries, and accidents are also not unusual (The Star).
These poor tannery workers suffer at their jobs every day because they have no other choice; leather production is their only job option. Halting the leather industry would put hundreds of thousands of people around the world out of a job, and for workers in places such as Dhaka, Bangladesh, it would mean going hungry.
Instead of shutting down the leather industry, a better option would be to make sure wastewater is treated properly. Believe it or not, according to Dan Keys of KeysTec Environmental, tanneries are in fact able to “clean up the water enough for it to be returned to nature with no harm. Industrial water is cleaned up in three stages:
1. Primary Treatment (Physical-Chemical Treatment).
2. Secondary treatment (biological treatment facility).
3. Tertiary Treatment (nature's final biological treatment).
The key is for the tanneries to clean up the water before it is returned to nature.” This would make all the difference for place like Dhaka, Bangladesh, where the Buriganga River runs black with pollution and has no fish due to the 21,000 cubic meters of untreated waste dumped into every day (The Star).
These poor tannery workers suffer at their jobs every day because they have no other choice; leather production is their only job option. Halting the leather industry would put hundreds of thousands of people around the world out of a job, and for workers in places such as Dhaka, Bangladesh, it would mean going hungry.
Instead of shutting down the leather industry, a better option would be to make sure wastewater is treated properly. Believe it or not, according to Dan Keys of KeysTec Environmental, tanneries are in fact able to “clean up the water enough for it to be returned to nature with no harm. Industrial water is cleaned up in three stages:
1. Primary Treatment (Physical-Chemical Treatment).
2. Secondary treatment (biological treatment facility).
3. Tertiary Treatment (nature's final biological treatment).
The key is for the tanneries to clean up the water before it is returned to nature.” This would make all the difference for place like Dhaka, Bangladesh, where the Buriganga River runs black with pollution and has no fish due to the 21,000 cubic meters of untreated waste dumped into every day (The Star).
Pollution in the Buriganga River. Photo credit: Autumn Foundation
When all is considered, the best option is not to stop the leather industry altogether; it would be to create regulations and practices that would make the leather production process more sustainable, and for country officials to enforce those laws. Doing so would not only help those who work directly in the industry, but it would also greatly benefit the environment.
WHAT CAN BE DONE TO MAKE THE LEATHER PRODUCTION PROCESS MORE SUSTAINABLE
SYNTHETIC MATERIAL
Leather is the hide of a deceased animal, which by nature, decomposes. The purpose of the toxic chemicals used by the leather tanning facilities is to prevent decomposition from occurring. Therefore, using synthetic leather as opposed to actual leather would greatly reduce the amount of pollution being put into the environment through the tanning process.
Synthetic leather is also not the only alternative; there are plenty of other plant-based or sustainable and renewable fabrics available such as cork, wood, linen, hemp, cotton, bamboo, ultrasuede, etc. Using these materials in place of leather would make a significant difference in terms of environmental impact (Ecouterre).
WHAT CAN BE DONE TO MAKE THE LEATHER PRODUCTION PROCESS MORE SUSTAINABLE
SYNTHETIC MATERIAL
Leather is the hide of a deceased animal, which by nature, decomposes. The purpose of the toxic chemicals used by the leather tanning facilities is to prevent decomposition from occurring. Therefore, using synthetic leather as opposed to actual leather would greatly reduce the amount of pollution being put into the environment through the tanning process.
Synthetic leather is also not the only alternative; there are plenty of other plant-based or sustainable and renewable fabrics available such as cork, wood, linen, hemp, cotton, bamboo, ultrasuede, etc. Using these materials in place of leather would make a significant difference in terms of environmental impact (Ecouterre).
Synthetic leather. Photo credit: Chic Steals
“GREEN” LEATHER
According to Phys.org, scientists at the Central Leather Research Institute in India have established a way to modify the tanning process in order to make it more eco-friendly and cost-efficient with no observable loss of leather quality. Researchers found that simply reversing the order of the tanning and post-tanning steps, while simultaneously promoting non-chemical-based pre-tanning methods, reduced the amount of chemicals released by 82% and made an energy saving of nearly 40%. These findings were published in the Journal of Chemical Technology and Biotechnology. According to the head of this study, Raghava Rao, “The significance is tremendous in the context of environmental challenges being faced by the leather industry.”
TILEATHER
Beginning in 2010, the European Union funded a project called Tileather ('Ecofriendly Leather Tanned with Titanium'). The main objective of this project was to develop a new chrome-free leather tanning method that would reduce the potential risk to humans and the environment. Tileather researchers came upon the idea of using titanium as an alternative to chrome, and it was soon found that titanium produces leather that is light and strong, yet is biocompatible with human tissues; it is innocuous, hypoallergenic and biodegradable. The new process eliminates chromium completely, while producing leather with similar properties.
Once the new process was established and tested, the project team began manufacturing the product under the trade name Sanotan, and supplied it to various producers.
Over the two years that Tileather was mannufactured, project partners say they managed to eliminate 25.5 tons of chromium compounds from their tanning processes while reducing their CO2 emissions by 35 tons (Phys.org).
According to Phys.org, scientists at the Central Leather Research Institute in India have established a way to modify the tanning process in order to make it more eco-friendly and cost-efficient with no observable loss of leather quality. Researchers found that simply reversing the order of the tanning and post-tanning steps, while simultaneously promoting non-chemical-based pre-tanning methods, reduced the amount of chemicals released by 82% and made an energy saving of nearly 40%. These findings were published in the Journal of Chemical Technology and Biotechnology. According to the head of this study, Raghava Rao, “The significance is tremendous in the context of environmental challenges being faced by the leather industry.”
TILEATHER
Beginning in 2010, the European Union funded a project called Tileather ('Ecofriendly Leather Tanned with Titanium'). The main objective of this project was to develop a new chrome-free leather tanning method that would reduce the potential risk to humans and the environment. Tileather researchers came upon the idea of using titanium as an alternative to chrome, and it was soon found that titanium produces leather that is light and strong, yet is biocompatible with human tissues; it is innocuous, hypoallergenic and biodegradable. The new process eliminates chromium completely, while producing leather with similar properties.
Once the new process was established and tested, the project team began manufacturing the product under the trade name Sanotan, and supplied it to various producers.
Over the two years that Tileather was mannufactured, project partners say they managed to eliminate 25.5 tons of chromium compounds from their tanning processes while reducing their CO2 emissions by 35 tons (Phys.org).
ORGANIC LEATHER
Organic Leather is a leather production company that uses only certified organically raised cows and tans its leather with all natural biodegradable tanning materials. A finished organic leather product is free of the toxic chemicals regularly found in tanned leather such as chrome, formaldehyde, sulfuric acid, etc. Not many in the leather industry opt for this much lengthier method of production (chrome-tanned leather takes under a week, while organic leather takes 5 weeks to 12 months), but it is slowly growing in numbers as the word spreads and people become more environmentally-conscious.
Organic Leather is a leather production company that uses only certified organically raised cows and tans its leather with all natural biodegradable tanning materials. A finished organic leather product is free of the toxic chemicals regularly found in tanned leather such as chrome, formaldehyde, sulfuric acid, etc. Not many in the leather industry opt for this much lengthier method of production (chrome-tanned leather takes under a week, while organic leather takes 5 weeks to 12 months), but it is slowly growing in numbers as the word spreads and people become more environmentally-conscious.
Organic leather. Photo credit: Organic Leather
REUSING WATER, REDUCING FRESH WATER USE, AND CLEANING WASTEWATER
Simona Tanning, a relatively new facility in Huizhou, China, and whose list of clients includes Clarks, Keen, Nike, and Timberland, has created a system to reduce water waste. A membrane bio reactor reduces the amount of suspended solids and organic pollutants in water used to re-tan the hides and a reverse osmosis system filters the treated water so it can be reused in the tanning process. According to WWD, the system has reduced the facility's fresh water use and water discharge by 40 percent (Treehugger). Dan Keys of KeysTec Environmental, however, warns that reusing tannery water too much builds up inorganic components that cannot be removed in the three stages of industrial water clean-up. Keys says, “Some select reuse can be done, but not total reuse.”
Dan Keys also states that tanneries are able to “clean up the water enough for it to be returned to nature with no harm. Remember that industrial wastewater is cleaned up in three stages:
1. Primary Treatment (Physical-Chemical Treatment).
2. Secondary treatment (biological treatment facility).
3. Tertiary Treatment (nature's final biological treatment). The key is for the tanneries to clean up the water before it is returned to nature.”
Simona Tanning, a relatively new facility in Huizhou, China, and whose list of clients includes Clarks, Keen, Nike, and Timberland, has created a system to reduce water waste. A membrane bio reactor reduces the amount of suspended solids and organic pollutants in water used to re-tan the hides and a reverse osmosis system filters the treated water so it can be reused in the tanning process. According to WWD, the system has reduced the facility's fresh water use and water discharge by 40 percent (Treehugger). Dan Keys of KeysTec Environmental, however, warns that reusing tannery water too much builds up inorganic components that cannot be removed in the three stages of industrial water clean-up. Keys says, “Some select reuse can be done, but not total reuse.”
Dan Keys also states that tanneries are able to “clean up the water enough for it to be returned to nature with no harm. Remember that industrial wastewater is cleaned up in three stages:
1. Primary Treatment (Physical-Chemical Treatment).
2. Secondary treatment (biological treatment facility).
3. Tertiary Treatment (nature's final biological treatment). The key is for the tanneries to clean up the water before it is returned to nature.”
