Plastic shopping bags, carrier bags or plastic grocery bags are a type of shopping bag made from various kinds of plastic, and are common worldwide. These bags are sometimes called single-use bags, referring to carrying items from a store to a home. However, reuse for storage or trash is common, and modern plastic shopping bags are increasingly recyclable or biodegradable.
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US and European patent applications relating to the production of plastic shopping bags can be found dating back to the early 1950s, but these refer to composite constructions with handles fixed to the bag in a secondary manufacturing process.
The modern lightweight shopping bag is the invention of Swedish engineer Sten Gustaf Thulin.[1] In the early 1960s, Thulin developed the idea for forming a simple one-piece bag by folding, welding and die-cutting a flat tube of plastic in the early 1960s for packaging company Celloplast of Norrköping, Sweden. Thulin's design produced a simple, strong bag with a high load-carrying capacity, and was patented worldwide by Celloplast in 1965.
Celloplast was a well-established producer of cellulose film and a pioneer in plastics processing. The company's patent position gave it a virtual monopoly on plastic shopping bag production, and the company set up manufacturing plants across Europe and in the US. However, other companies saw the attraction of the bag, too, and US petrochemicals group Mobil overturned the Celloplast US patent in 1977.
The Dixie Bag Company of College Park, Georgia, owned and operated by Jack W. McBride, was one of the first companies to exploit this new opportunity to bring convenient products to all major shopping stores. The Dixie Bag Company, along with similar firms such as Houston Poly Bag and Capitol Poly, was instrumental in the manufacturing, marketing and perfecting of plastic bags in the early 1980s. Kroger, a Cincinnati-based grocery chain, began to replace its paper shopping bags with plastic bags in 1982,[2] and was soon followed by its rival, Safeway.[2]
Without its plastic bag monopoly, Celloplast's business went into decline, and the company was split up during the 1990s. The Norrköping site remains a plastics production site, however, and is now the headquarters of Miljösäck, Sweden’s largest producer of waste sacks manufactured from recycled polyethylene.
From the mid-1980s onwards, plastic bags became common for carrying daily groceries from the store to vehicles and homes throughout the developed world. As plastic bags increasingly replaced paper bags, and as other plastic materials and products replaced glass, metal, stone, timber and other materials, a packaging materials war erupted, with plastic shopping bags at the center of highly publicized disputes. Although few peer-reviewed studies or government surveys have provided estimates for global plastic bag use, environmental activists estimate that between 500 billion and 1 trillion plastic bags are used each year worldwide.[3] In 2009, the United States International Trade Commission reported that the number of bags used annually in the USA was 102 billion.[4]
Traditional plastic bags are usually made from polyethylene, which consists of long chains of ethylene monomers. Ethylene is derived from natural gas and petroleum. The polyethylene used in most plastic shopping bags is either low-density (resin identification code 4) or, more often, high-density (resin identification code 2).[5] Plastic shopping bags are commonly manufactured by blown film extrusion.
Some modern bags are made of vegetable-based bioplastics, which can decay organically and prevent a build-up of toxic plastic bags in landfills and the natural environment. Bags can also be made from degradable polyethylene film. However, most degradable bags do not readily decompose in a sealed landfill[6] and represent a possible contaminant to plastic recycling operations. Plastic shopping bags could be made from polylactic acid (PLA), a biodegradable polymer derived from lactic acid, although this is not widely used.[7]
According to Vincent Cobb, a manufacturer of reusable bags, each year millions of discarded plastic shopping bags end up as litter in the environment when improperly disposed of.[8] The same properties that have made plastic bags so commercially successful and ubiquitous—namely their low weight and resistance to degradation—have also contributed to their proliferation in the environment. Due to their durability, plastic bags can take centuries to decompose.[8]
On land, plastic bags are one of the most prevalent types of litter in inhabited areas. Large buildups of plastic bags can clog drainage systems and contribute to flooding, as occurred in Bangladesh in 1988 and 1998[9] and almost annually in Manila.[10][11]
Plastic bags were found to constitute a significant portion of the floating marine debris in the waters around southern Chile in a study conducted between 2002 and 2005.[12] If washed out to sea, plastic bags can be carried long distances by ocean currents, and can strangle marine animals or, if ingested, cause them to starve to death.[8] Numerous deaths among animals such as sea turtles and dolphins have been attributed to the ingestion of plastic marine littwhich includes plastic bags.[13]
Littering is often a serious problem in developing countries, where trash collection infrastructure is less developed than in developed nations.[14] The relatively limited adoption of modern biodegradable plastic bags means that many older landfills are filled with large, persistent deposits of non-degrading bags.
Heavy-duty plastic shopping bags are suitable for reuse as reusable shopping bags. Lighter weight bags are often reused as bin bags (trash bags) or to pick up pet faeces. All types of plastic shopping bag can be recycled into new bags where effective collection schemes exist.
Since internet rumours started to claim that the Environmental Protection Agency had reported only 1% of plastic bags were recycled, significant attention resulted in a 700% growth in the recycling industry as new capacity led to a 7% rate. This resulted in more than 800 million lbs of bags and other film being recycled in 2007 alone[15] Each ton of recycled plastic bags saves the energy equivalent of 11 barrels of oil, although most bags are produced from natural gas derived stock.[16] In light of an Australian study showing more than 60% of bags are reused as bin liners and for other purposes,[17] the 7% recycling rate accounts for 17.5% of bags available for recycling.
According to the UK's Environment Agency, 76% of British carrier bags are reused.[18] An estimated 90% of individuals reuse some plastic bags, and 56% of individuals reuse all plastic shopping bags.[19] Heavier-duty plastic shopping bags are suitable for multiple uses as reusable shopping bags.
Plastic bags are either restricted or completely banned in over a quarter of the world's countries.[20] Belgium, Italy, Ireland and Hong Kong have legislation discouraging the use and encouraging the recycling of plastic bags by imposing a fixed or minimum levy for the supply of plastic bags or obliging retailers to recycle.[21][22][23] Italy banned plastic bags entirely in January 2011. In other jurisdictions, including Bangladesh, South Africa and three states/territories of Australia, plastic bags are banned.[24][25]
In the United States, bans have been imposed at the local level, starting with San Francisco in 2007. In 2008, Westport, Connecticut, banned plastic bags in grocery stores.[20][26] In 2009, Edmonds, Washington, banned plastic bags at retail stores.[27] In 2010, Los Angeles County; Brownsville, Texas; and Bethel, Alaska, approved similar bans.[28][29] During the first few months of 2011, bans went into effect in North Carolina’s Outerbanks Region, banning all plastic bags at all retailers.[30] On October 15, 2011, Portland, Oregon, instituted a ban on plastic bags, targeted at large-volume supermarkets and retail outlets.[31] Seattle, Washington, followed suit on December 19, 2011, when its city council voted unanimously to ban single-use plastic bags from grocery stores and other retail outlets.[32] Similar plastic-bag bans have been imposed at the municipality level in India, Mexico and the United Kingdom.[21]
A plastic bag levy introduced in Ireland in 2002 resulted in a reduction of over 90% in the issuing of plastic shopping bags;[33] the total reduction in plastic bag use was less than that due to increased use of commercial trash bin-liners in place of the free shopping bags previously used by many consumers. Sales of bin-liners have increased by 400% according to one industry source.[34] The "ban on free plastic bags" in China introduced in 2008 resulted in a reduction by two thirds.[35] In Taiwan, plastic bags from supermarkets and other shops cost NT$2. In Wales, a 5-pence charge has been enforced on all plastic shopping bags since 1 October 2011.[36]
In the United States, the California legislature rejected a 25-cent bag tax in June 2009.[37] In August 2009, Seattle voters rejected a 20-cent bag tax previously approved by city leaders.[38] A five-cent tax levied on plastic bags in Washington, DC in January 2010 resulted in a decrease in consumption from 22.5 million to 3 million bags in the first month alone.[39] A study issued by the non-profit group American for Tax Reform found that the District of Columbia’s five-cent bag tax had a disproportionate impact on the city’s poor and cost the city over 100 jobs.[40] In Virginia, various bills including a 20-cent and 5-cent bag tax failed to pass the state senate.[41] A similar tax failed to move forward in nearby Prince George's County, Maryland, in April 2011, and opponents cited concerns about jobs and the economy.[42] Montgomery County, Maryland, approved a five-cent tax in May 2011.[43]
Many cities and states in the United States – including California, New York, Chicago, Delaware and Baltimore – have addressed bag litter and landfill by enacting new recycling laws.[44][45][46][47][48]
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