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This report was prepared on behalf of the U.S. EPA Region 10 and the West Coast Climate and 

Materials Management Forum by the Forum’s Materials Management & Product Stewardship 

Workgroup. Special thanks to all of the EPA staff and Forum members who reviewed drafts, offered 

revisions, and contributed to the final product. Specifically, we acknowledge the contributions of 

workgroup leaders Bill Smith of the City of Tacoma Solid Waste Management Division and John 

Davis of the Mojave Desert and Mountain Recycling Authority, as well as EPA NNEMS Fellows 

McKenna Morrigan and Evan Johnson. Questions about the report may be directed to Ashley Zanolli, 

Environmental Engineer, U.S. EPA Region 10. To learn more about the West Coast Climate and 

Materials Management Forum, visit http://www.epa.gov/region10/westcoastclimate.htm

/01'(.%2.3%$,($,-

Introduction .......................................................................................................................................... 2

Section 1. Objectives and Rationale for Our Project .............................................................................. 4

Section 2. Research Design and Methodology ....................................................................................... 5

Section 3. Using WARM to Identify Priority Materials for Emissions Reduction ................................. 7

Section 4. Implications for Emissions Reductions and Carbon Offsets ............................................... 10

Section 5. Additional Benefits of Recycling and Composting Priority Materials ................................. 12

Section 6. Opportunities for Reducing Emissions through Recycling and Composting ...................... 14

Section 7. Summary Reflections and Next Steps .................................................................................20

APPENDIX A: State Waste Tonnage Data by WARM Category........................................................... 22

APPENDIX B: WARM Per Ton Emissions Estimates for Alternative Management Scenarios ............ 24

APPENDIX C: Concerns with WARM Emissions Factor for Carpet Recycling .................................... 25

APPENDIX D: Proportions of Waste from Commercial and Residential Substreams ......................... 26

APPENDIX E: Benefits and Limitations of WARM Model .................................................................. 27

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Figure 1 Sector-based accounting of U.S. GHG Emissions .................................................................... 4

Figure 2 Systems-based accounting of US GHG Emissions................................................................... 4

Table 1: Materials with Highest Potential for GHG Emissions Reduction, by State ..............................8

Figure 3: Net Annual Emissions Reduction Potential of Recycling and Composting ............................ 9

Table 2: Emissions Reduction Goals Relative to Potentials of Recycling and Composting .................. 11

Table 3: Additional Revenue Potential from Recycling and Composting ............................................ 13
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The West Coast Climate and Materials Management Forum, an EPA-led partnership of western local, 

state, and tribal governments, established a Materials Management & Product Stewardship 

Workgroup to identify key materials management strategies that could be used by local governments 

to reduce greenhouse gas (GHG) emissions in the near term.

The workgroup began by focusing on the life-cycle impacts of materials currently being disposed in 

landfills and the GHG emissions reductions that are possible by diverting discarded materials from 

landfills through recycling and composting. Although additional materials management approaches,

including reuse, remanufacturing, source reduction, material reduction/substitution, 

environmentally preferable purchasing, upstream design and manufacturing changes, also promise 

significant emissions reductions, the scope of this paper is limited to evaluating only recycling and 

composting. Future Workgroup projects will focus more on the emissions reduction potential of these 

other approaches.

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This report is intended to help governments and other organizations make informed and strategic 

decisions about how to direct their limited resources toward end-of-life management of materials 

that provides the most significant impact on life-cycle greenhouse gas emissions. The report also 

provides rationale, from a climate action, economic and pollution prevention perspective, for local 

jurisdictions to adopt and implement recycling and composting initiatives in their communities.

We hope this report continues to build a unified intellectual foundation from which to consider 

climate change in a materials management context. We also hope it opens opportunities for strategic 

regional cooperation to improve materials management approaches to reduce emissions attributable 

to goods and food throughout their life cycle. 

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The analysis uses the U.S. EPA’s Waste Reduction Model (WARM) Calculator to estimate the GHG 

emissions attributable to materials in the waste streams of California, Oregon, and Washington, and 

to identify the materials with the greatest emissions reduction potential if recycled or composted 

rather than landfilled.

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This report draws on the WARM results to highlight ten materials, broken into four priority material 

types with the greatest emissions reduction potential (presented alphabetically): 

• Carpet

• Core Recyclables

• Corrugated containers

• Office paper

• Aluminum cans

• Newspaper

• Magazines

• PET and HDPE (or mixed plastics) 

• Steel cans

• Dimensional Lumber

• Food Scraps

Section 1 of this report outlines the objective and rationale for our analysis. 

Section 2 describes the research design and methodology used, including a brief introduction to the 

WARM Calculator and how it can be used. 

Section 3 presents the findings of our analysis for each state and across the three states. 

Section 4 discusses the implications of our analysis and describes how the results relate to local and 

state policy goals for emissions reductions. 

Section 5 highlights additional benefits of recycling and composting these priority materials, 

including job creation, economic development, and reduced land and marine pollution. 

Section 6 briefly describes opportunities for reducing emissions through recycling/composting of 

our four priority material types. 

Section 7 provides summary reflections and concludes with comments about how the Materials 

Management workgroup will explore ways to further reduce life-cycle emissions of materials through 

research on additional sustainable materials management practices. 
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Traditional, sector-based accounting of GHG emissions obscures the importance of materials 

management in addressing global climate change. Figure 1 depicts a typical accounting of GHG 

emissions, attributing the majority of impacts to the industrial, transportation, and electric power 

sectors.1 In this accounting, methane emissions generated by landfills (included under the 

Commercial sector) account for 1.8% of total U.S. GHG emissions. While the sector-based approach is 

useful for highlighting opportunities for end-of-pipe emissions reduction strategies, this accounting 

fails to illustrate the emissions associated with the life cycles of materials and land management

practices.

In a September 2009 report, Opportunities to Reduce Greenhouse Gas Emissions through Materials 

and Land Management Practices, the U.S. EPA employed a systems-based accounting method to 

categorize U.S. GHG emissions. Figure 2 depicts the EPA’s approach.2 The systems-based accounting 

reveals that 42% of emissions result from materials management, i.e. the extraction of natural 

resources, and production, transport and disposal of food and goods.3

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Expanding the scope of the EPA’s report, the Product Policy Institute took EPA’s National Emissions 

Inventory (NEI), subtracted out the emissions associated with exports and added in emissions 

associated with imports to the US. This provides a more accurate view of the emissions associated 

with goods used in the US. Under this global view of emissions associated with the US economy, 

overall GHG emissions are 12% higher than domestic emissions, and 44% of the total are associated 

with the production, transport, and end-of-life management of non-food materials alone.

4

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Current trends in production, consumption, and waste management have led to enormous emissions 

of heat-trapping greenhouse gases. The sources of such emissions are numerous, ranging from 

carbon dioxide released during the extraction and production of new materials to methane from the 

decomposition of organic waste in landfills.

Although the direct GHG emissions reductions achieved by landfill diversion are limited, the 

potential upstream impacts are much higher, if the end-of-life strategies used are able to reduce 

future emissions generated through the provision of goods and food. For example, diversion of 

aluminum from landfills for recycling offers minimal reductions in landfill emissions, but the use of 

recycled aluminum reduces emissions by reusing the material. The energy input of producing a ton of 

aluminum, which is directly linked to emissions output, is 96% lower when recycled aluminum is 

used. This is due to the elimination of the mining and smelting process required for virgin 

aluminum.

5

 Thus, end-of-life materials management strategies such as recycling can lead to 

significantly lower emissions from early stages in the material life cycle, including material 

extraction, manufacturing, and distribution. 

This report seeks to quantify those potential life-cycle emissions reductions that could be achieved by 

recycling or composting waste currently being landfilled in California, Oregon, and Washington. By 

identifying the materials with the greatest emissions reduction potential, the analysis reveals that 

some of these emission reductions can be achieved in the short term through existing recycling 

infrastructure, while others will require new infrastructure and programs to divert these priority 

materials from disposal.

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Our analysis uses recent, state-level waste characterization data from California, Oregon, and 

Washington.6,

7,8

 It is important to note that the this analysis uses data on the amount of materials 

currently being disposed of and does not analyze the emissions reductions of materials already being 

diverted from disposal. While it is possible to estimate the emissions reductions from existing

recycling and composting programs, the goal of this report is to identify the additional emissions 

reduction potential possible through recycling and composting materials still being discarded as 

waste, so only data on materials currently disposed are included. To identify the top ten materials by 

emissions reduction potential based on quantity of material available for recovery, we used the Waste 

Reduction Model (WARM) created by the U.S. Environmental Protection Agency (EPA).

The EPA created WARM to help solid waste planners and organizations estimate greenhouse gas 

(GHG) emission reductions from several different waste management practices. WARM is available 

as a Web-based calculator format and as a Microsoft Excel© spreadsheet. Both versions of WARM 

are available on the EPA's Web site.9

WARM calculates GHG emissions based on a comparison of a baseline and alternative waste 

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management practice, including source reduction, recycling, combustion, composting, and 

landfilling. The model calculates emissions in metric tons of carbon equivalent (MTCE) or metric 

tons of carbon dioxide equivalent (MTCO2E) across a wide range of material types commonly found 

in municipal solid waste (MSW). WARM users can construct various scenarios by simply entering 

data on the amount of waste handled by material type and by management practice. WARM then 

automatically applies material-specific emission factors for each management practice to calculate 

the GHG emissions and energy use of each scenario. 

Several key inputs, such as landfill gas recovery practices and transportation distances to MSW 

facilities, can be modified by the user. For this analysis, estimated tons of materials disposed, drawn 

from each state’s waste characterization study, were entered into the WARM Calculator. The WARM 

Calculator quantified the GHG emissions reductions comparing two waste management scenarios: 1) 

all of the materials are deposited in landfills; and 2) all of the materials are instead recycled or 

composted. Although a small amount of waste disposed of in California, Oregon and Washington is 

incinerated, the large majority is disposed of in landfills, making this a reasonable, simplifying 

assumption. 

The emissions reduction potential of recycling or composting the materials disposed of in each state 

was then ranked from highest to lowest and results from all three states were then compared.

The resulting list of priority materials includes the top ten materials from each state’s list. For all 

other WARM inputs, the default settings were used. This includes whether Landfill Gas (LFG) control 

systems are in place, what percentage of methane is captured, whether collected methane is flared or 

recovered for energy, and the assumed moisture conditions and associated bulk decay rate of 

disposed waste, (all of which affect the rate of methane emissions from landfills), as well as the 

assumed transport distances for landfilling, recycling, and composting, which affect the emissions 

associated with these various end-of-life management options.10,

11

Several difficulties persist for the accurate comparison of state waste measurements. First, waste 

policies differ across states and localities, leading to differences in the types of materials collected.

Second, how waste characterization studies define material categories and gather data varies across 

states. For instance, California and Washington specify plastic by polymer type (i.e. PET, HDPE, 

etc.), while Oregon specifies it by container type (i.e. bottle, tub) and by whether it is accepted in 

curbside recycling programs. Both Oregon and Washington specify 15 different types of paper, broken 

into “packaging” and “non-packaging” subcategories, while California lumps these together and 

includes fewer categories altogether. Even the 15 paper types differ somewhat between Oregon and 

Washington, frustrating comparisons. Third, the categories and definitions included in the WARM 

Calculator do not always correspond with state waste characterization studies. WARM users face the 

challenge of reconciling their materials category definitions with those the model employs. Our 

reconciling of categories for this analysis is presented in Appendix A. 

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These discrepancies make it challenging to estimate the emissions reduction opportunities across state 

and local governments. Nevertheless, we believe that comparing WARM results for California, Oregon, 

and Washington illustrates the opportunity for a common set of strategies for GHG emissions reduction 

through recycling and composting in various government arenas. The WARM results, which showed 

remarkable similarity across the states in terms of materials, appear to support this belief.

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The following section presents the WARM results for each of the three states featured in this report.

Despite incongruities between state measures and WARM features, as well as differences between the 

states themselves, commonalities of top materials with emissions reduction potential among the 

states are unambiguous. Table 1 identifies the top ten materials with the highest emissions reduction 

potential for each state. Each state’s WARM output is displayed graphically in Figure 3, which show 

the emissions reduction benefits of recycling the listed materials (or composting, in the case of food 

scraps), calculated against a baseline emissions scenario in which they are landfilled. 

The WARM results suggest that the greatest potential for emissions reduction across all three states 

can be achieved through better end-of-life management of ten materials, broken into four priority 

material types: 

• Carpet

• Core Recyclables

• Corrugated containers

• Office paper

• Aluminum cans

• Newspaper

• Magazines

• PET and HDPE (or mixed plastics) 

• Steel cans

• Dimensional Lumber

• Food Scraps

Carpet12, dimensional lumber, and food scraps appear in the top ten for all three states. Six of the 

seven materials comprising core recyclables also appear on all three lists. Of note among the core 

recyclables is corrugated containers, or cardboard, which alone constitutes half of the total potential 

of all core recyclables in California and Oregon and roughly one third of emissions reduction 

potential of core recyclables in Washington. 

There are two factors that determine which materials rank highest in terms of emissions reduction 

potential: first, the GHG emissions reduction potential of recycling or composting each material on a 

per ton basis according to WARM; second, the overall tonnage of each material that is disposed, 

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relative to the tonnage of other materials disposed in the state. Most of the materials listed above

rank high in GHG emissions reduction potential on a per ton basis, even though they make up a 

relatively small proportion of total waste disposed. 

Food scraps are the exception, in that WARM does not assign them a particularly high emissions 

reduction potential per ton, but they nonetheless appear in the top ten because they make up a 

significant portion of disposed waste. The per ton emissions factors used in the WARM calculations 

are listed in Appendix B.

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All three West Coast states have set goals for reducing greenhouse gas emissions. Our analysis shows 

that recycling and composting can produce significant emissions reductions, and are thus compelling 

tools to include in climate plans. It is worth recognizing that some of the life-cycle emissions for 

waste disposed in California, Oregon, and Washington that are calculated using WARM are not 

generated exclusively (or even predominantly) in these states. Emissions from resource extraction, 

manufacturing and transportation associated with materials used and discarded here sometimes 

occur outside of the region and would not be captured by most current state GHG inventory methods. 

To account for boundary issues, alternate methods for conducting inventories are being developed in 

several jurisdictions, including the State of Oregon and King County (WA), which are developing 

consumption-based inventories that account for emissions generated outside their boundaries as a 

result of consumption within their boundaries. The Inventory Workgroup of the West Coast Climate 

and Materials Management Forum has developed a toolkit for other jurisdictions interested in 

including consumption-based methods into emissions inventories.

15

Even in jurisdictions that have not yet adopted consumption-based inventory methods, some GHG 

emissions associated with materials management, such as from long-distance trucks delivering goods 

and hauling solid waste out of state, are undoubtedly generated within these states and are included 

in existing state GHG emissions inventories. In these cases, reductions in these emissions due to 

recycling and composting would be captured by the states’ inventories and contribute toward 

emissions reduction goals. In addition, methane emissions reductions due to diversion of food scraps 

would likely be captured, as these emissions are often counted in conventional inventories. 

N+5--5%$-.=()7",5%$

Diversion of food scraps from landfills offers the greatest quantity of in-state GHG emissions 

reductions. Food scraps are responsible for a large share of methane emissions generated by landfills, 

and while landfill emissions comprise only a small portion of life-cycle emissions attributable to 

goods and food, they nonetheless represent a real opportunity for emissions reduction. This is largely 

due to the large quantities of food that is wasted and sent to landfills.

According to our analysis, the emissions reduction potential of diverting one year’s worth of food 

scraps from landfills through composting is equal to approximately 1.5% of California’s 2050 

emissions reduction goal, 0.8% of Oregon’s goal, and 1.8% of Washington’s goal. Note that these are 

not one-to-one comparisons—the 2050 emissions reduction goals are the emissions that must be 

reduced on an annual basis, while the emissions reductions quantified by the WARM Calculator are 

life-cycle emissions that occur over many years based on a single year’s food waste—but are simply 

intended to provide a sense of scale.

16

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The California Environmental Protection Agency Air Resources Board has recently issued a draft 

compost emissions reduction factor (CERF) as part of its rulemaking process for its AB 32 Mandatory 

Commercial Recycling regulations.

23

Whereas the WARM emissions factor for compost only considers 

the carbon storage effects, the CERF includes emissions reductions due to decreased water use, 

decreased soil erosion, and reduced fertilizer and herbicide use, as well as increased carbon storage 

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in soil. As a result, the CERF places the emissions reduction potential of compost at 0.42 

MTCO2e/ton of food scraps, more than twice as high as the WARM factor of 0.20 MTCO2e/ton. If this 

report’s calculations were done using the CERF, the total emissions reduction potential of 

composting food scraps would be even higher.

The WARM Calculator only evaluates the relative methane emissions reductions of open windrow 

composting, but GHG emissions reductions can also be achieved by managing food scraps through

alternative composting methods (such as static aerated piles or enclosed systems) and by anaerobic 

digestion. When anaerobically digested, food scraps can also be used as an alternative energy source. 

The methane generated during decomposition can be captured and converted to a natural gas 

equivalent fuel, or used to power a turbine to generate electricity.

3081%$.38()5,-]H22-(,-

In addition to directly reducing emissions, composting and anaerobic digestion of food scraps may 

also provide the opportunity to generating emissions offset credits. The Climate Action Reserve, 

North America’s largest carbon offset registry, issued an Organic Waste Digestion Protocol in 2009 

and recently established an Organic Waste Composting Protocol. These protocols set standards for 

the quantification and verification of GHG emissions reductions from composting and anaerobic 

digestion projects.

24 Projects adhering to the protocol and listed by the Reserve are eligible to sell 

carbon offset credits, known as CRTs, generated from the projects and revenue from CRT sales can 

help support private investment in composting and anaerobic digestion.25

>(",5%$.VE !))5,5%$0'.^($(25,-.%2.=("?"'5$*._.3%+;%-,5$*.:85%85,?.A0,(850'-

The WARM results of this analysis reveal that materials management can help states achieve 

emissions reductions. In addition, recycling and composting can contribute to other state and local 

policy goals, such as job creation, economic development, and reducing land and marine pollution.

`%1.38(0,5%$.0$).N"%$%+5".P(B('%;+($,

According to, “Recycling and Economic Development,” a literature review conducted by Cascadia 

Consulting Group for King County Solid Waste Division’s LinkUp program, increasing recycling can 

have positive benefits for job creation and economic development.

26

During a period in which many traditional manufacturing industries have been losing jobs in the U.S., 

several studies show that recycling has created manufacturing jobs, as well as jobs in recycling

 

24 For more information, visit !!!"#$%&'()'#(%*+,)-),.)"*,/01*!02,*(*#*$-0'3*2()30*,/'+%#4!'-()4

3%/)-(%*+0#5,,)+(06*,

!!!"#$%&'()'#(%*+,)-),.)"*,/01*!02,*(*#*$-0'3*2()30*,/'+%#4!'-()4#*&2*-(%+/0#5,,)+(0

25The first composting offset project, “Z-Best Food Waste Composting,” was listed by the Climate Action Reserve on 

February 2. For more information, visit www.cawrecycles.org/files/zanker.pdf

26 Cascadia Consulting Group, “Recycling and Economic Development: A Review of Existing Literature on Job Creation, 

Capital Investment, and Tax Revenues.” (King County Solid Waste Division LinkUp, April 2009).
!"#$%&'()*+""',-$.")*/.)01&..&-'.)2,+-$(,)!"%3%4&'()/'#)5-16-.2&'() :8

processing.

27

Additional research on the U.S. labor market suggests that recycling results in ten times 

the jobs of waste disposal.

28

And jobs in the recycling industry pay more, on average, than that 

national average wage.

29

In 2001, CalRecycle (formerly the California Integrated Waste Management Board) released a study 

showing that diverting a ton of recyclable or compostable material has approximately twice the

economic impact of sending it to a landfill. According to the report, diverting one additional ton of 

waste would pay $101 more in salaries and wages, produce $275 more in goods and services, and 

generate $135 more in sales than disposing of it in a landfill.

30

Using these figures, if just half of core recyclables and food scraps reported here that are currently in 

the waste streams of California, Oregon, and Washington were recycled, that would result it almost 

$1.6 billion in additional salaries and wages, $818 million in additional goods and services produced, 

and $309 million in additional sales across the three states. These gains would translate into 

additional revenue for state and local governments as well, through income, property, and sales taxes.

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Market values of several recyclable materials, such as cardboard and aluminum, have increased 

substantially in the ten years since the CalRecycle analysis was conducted, meaning that the figures 

above are lowered than might be expected today.

31

Estimates of the job and economic benefits are not 

available for carpet or dimensional lumber recycling, but they would also likely add hundreds of 

millions more to these figures.

=()7"().40$).0$).A085$(.:%''7,5%$

According to the 2004 Washington State Litter Study, 1,125 tons of plastic or metal beverage containers, 

cardboard, newspaper, magazines, food waste, carpet and wood were deposited on Washington 

roadways. Together these materials accounted for 17.8% of the total material littered.

32

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Marine pollution, demonstrated most visibly by the “Great Pacific Garbage Patch” in the northern 

Pacific gyre, is now a major environmental concern. Research has found that the mass of plastics in 

the gyre now exceeds the total mass of living creatures (plankton) by 6 to 1. Worldwide, plastics 

comprise 60 to 80 percent of marine debris on average, with some areas as high as 90 to 95 percent. 

Urban runoff—material entering the water via storm drains or being swept or blown into the water—

is the primary source of marine debris and litter is the major source of trash in urban runoff.

33

 Litter

makes its way to the ocean through the storm drainage systems and waterways, by wind action and by 

direct disposal into the water. 

Any efforts that increase recycling and composting and reduce disposal and littering will help reduce 

the amount of materials that end up in our waterways and oceans and reduce threats posed to the 

animals that call the ocean their home.

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9E 308;(,

Although carpet comprises only 3% of the waste stream in terms of tonnage in California, Oregon, 

and Washington, it is a material with one of the highest emissions reduction potentials through 

recycling in all three states.

34

 Carpet is made from natural gas and petroleum products and requires a 

great deal of energy to produce. Most carpet in the U.S. is manufactured in Southern states, where 

energy is derived largely from coal. The tremendous fossil fuel intensity of carpet inputs and 

production makes the emissions of carpet manufacturing extremely high. 

For many years, recycling carpet was technically challenging, expensive, and impractical. However, 

new techniques and advances in recycling infrastructure are making recycling carpet more viable. 

Several carpet manufacturers have developed processes for turning used carpet into new carpet, with 

much lower life-cycle emissions than manufacturing with virgin content. Carpet can also be recycled 

into other products, such as carpet pad or molded plastic parts (often for automobiles), also leading 

to significant emissions reductions. However, carpet recycling requires source separation for clean, 

high-value feedstock, which requires participation from private construction and demolition (C&D) 

firms.

The U.S. carpet industry has had voluntary recycling programs in place for over a decade but recycling 

rates remain relatively low. In 2002, members of the carpet industry, representatives of government 

agencies at the federal, state and local levels, and non-governmental organizations signed a 

Memorandum of Understanding for Carpet Stewardship (MOU) to improve carpet diversion and 

recycling through voluntary product stewardship. Product stewardship is a product-centered approach 

to environmental protection that calls on those in the product life cycle—manufacturers, retailers, 

users, and disposers—to share responsibility for reducing the environmental impacts of products.

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G/%2-+)$."#@)%/+6"2)+"%3%4&'()%4"/+43)-GG"+.)2+"1"'#-$.)"1&..&-'.)+"#$%2&-')6-2"'2&/4D
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The agreement set an official goal of 40% landfill diversion, including a 20-25% recycling rate for 

post-consumer carpet, by 2012, and established the Carpet American Recovery Effort (CARE) to 

achieve these targets. An annual report published by CARE in 2009, however, revealed a growing gap 

between the yearly goals for diversion and recycling and the actual levels reported. In 2009, for 

example, the recycling rate missed CARE’s 13% goal by 8.8%, with only a 4.2% rate being achieved. 

Overall diversion (including combusting carpet for energy production) totaled only 5.3%, 15.7 points 

lower than the 21% goal.

35

To achieve higher diversion rates, several states have begun exploring mandatory product 

stewardship policies and in October 2010, the California legislature passed the first carpet product 

stewardship bill in the country. AB 2398 requires every producer of carpet sold in the state of 

California, individually or through a designated stewardship organization, to submit a stewardship 

plan, including a funding mechanism that provides sufficient funding to carry out the plan, and to 

demonstrate continuous meaningful improvement in the rates of recycling and diversion and other 

specified goals in order to be in compliance.

36

In the Northwest, a similar bill, SB 5110

37

, was considered in the 2011 Washington legislative session. 

In addition, state and local government groups have formed the Northwest Carpet Recycling 

Workgroup in 2009, which is actively working to increase demand for carpet recycling and products 

made with recovered carpet fiber, and to encourage carpet processing facilities to become established 

in the northwest for economic development and easier carpet recycling.

38

 The effort, along with the 

significant contributions of private industry, has been successful and new carpet recycling facilities 

have opened in the area.

In 2009 CARE initiated another round of negotiations to develop a new ten-year MOU agreement 

among stakeholders toward setting and meeting new carpet landfill diversion goals. 

99E 3%8(.=("?"'01'(-

Since the first municipal recycling programs began in the 1970’s, curbside collection of recyclables 

has spread throughout the West Coast and across the United States. A recent survey estimates that 

74% of the U.S. population currently has access to curbside recycling collection.

39

 Although the types 

of materials included in curbside recycling varies from place to place, most programs cover a core set 

of recyclable materials including aluminum and steel food and beverage containers, newspapers, 

magazines, high-grade paper, corrugated cardboard containers, and #1 and #2 plastic bottles. Many 

curbside recycling programs also accept glass containers and a wider array of paper and plastic types. 

Cities with the most successful curbside recycling programs have used variable rate pricing structures 

to incentivize recycling participation.

40

 This approach, often called “Pay As You Throw,” or PAYT, sets 

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garbage collection charges on a per unit or weight basis, rather than charging a flat fee for unlimited 

garbage collection. In addition, most PAYT programs provide recycling collection at free or reduced 

rates, making it economically attractive for waste generators to divert recyclable materials from 

landfill disposal. Communities with PAYT programs in place have reported significant increases in 

recycling and reductions in waste. Overall, PAYT programs have been shown to reduce disposal by 

about 17%, with 5-6% being directly diverted to recycling.

41

West Coast cities have been leaders in instituting PAYT programs, and as a result these programs are 

widespread throughout the region. In fact, a recent survey of PAYT programs for the EPA estimates 

that virtually all communities in Washington and Oregon have PAYT programs in place, while half of 

California communities have them.

42

Curbside residential recycling programs in West Coast states continue innovating to increase 

participation and reduce contamination through public information and outreach, including focused 

social marketing. And Los Angeles recently began piloting a rewards-based approach in partnership

with Recyclebank.

43

 Recyclebank has been successful in increasing diversion of recyclables in 

Philadelphia, Cincinnati, and other large cities.

Although California, Oregon, and Washington have high diversion rates of recyclable materials 

compared to the national average, increasing recycling of core recyclables in these states can still 

deliver important benefits, such as emissions reduction, cost savings, and jobs. As this analysis 

shows, recyclable materials still appear in the disposed waste stream of West Coast states. In 

California, Oregon, and Washington, core recyclables make up 7-10% of disposed waste by weight, 

and are responsible for 33-55% of all emissions found in this analysis to be attributable to the top ten 

materials in each state. This suggests that there remains significant room for improvement in 

recycling programs and policies targeting diversion of core recyclables. 

Although already recycled at high rates, corrugated containers continue to appear in the waste 

streams of all three states in large quantities. Corrugated containers embody the third greatest 

emissions reduction potential of all materials currently landfilled, and represent a valuable recyclable 

commodity. An analysis of the waste characterization studies in California and Washington, which 

break their state waste data into substreams by source, reveals that corrugated containers come 

predominantly from commercial generators.

44

In California, although commercial sources are responsible for only 50% of total waste, the 

commercial substream generates 75% of all corrugated containers. In Washington, the commercial 

sector generates 44% of total waste but 55% of all corrugated containers. 

While residential recycling programs are mandatory in many places, commercial recycling remains 

largely voluntary, making it difficult for local and state governments to increase the diversion of 

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recyclable materials from the commercial waste stream. Recognizing the potential of increased 

recycling to reduce greenhouse gas emissions, California has begun taking steps to mandate 

commercial recycling statewide. The Mandatory Commercial Recycling Measure, being developed by 

CalRecycle as part of its implementation of the California Global Warming Solutions Act of 2006 

(AB 32), would require businesses generating 4 or more cubic yards of trash and/or recyclables for 

weekly collection to receive recycling services. This measure is intended to achieve GHG reductions 

of 5 million MTCO2e.

999E P5+($-5%$0'.47+1(8

Dimensional lumber is among the most easily diverted wood types, and is nonetheless disposed of in 

sufficiently large volume to rank among the top ten materials with emissions reduction potential in 

each of the three West Coast states. Wood comprises a surprisingly large portion of organic materials 

disposed of in landfills. The broad category of wood in waste characterization studies includes many 

different types of materials, such as “clean” (unpainted/untreated) lumber, painted/treated lumber, 

hogfuel, pallets, crates, and wood furniture. Some of these wood types, such as clean lumber, could be 

more easily diverted from disposal through recycling than others. Because of this, the WARM 

Calculator—and thus this analysis—focuses only on clean dimensional lumber. 

Dimensional lumber is a construction and demolition (C&D) waste with relatively good recycling 

options. According to CalRecycle (formerly California Integrated Waste Management Board), this 

type of wood waste is highly desirable and is sought by processors.

45 Lumber scraps generated during 

construction make an excellent feedstock for engineered wood, and can also be recycled into products 

such as laminates, parquet, pallets, countertops, shelving, furniture, mulch, wood pellets, and

fiberboard.

46 Some dimensional scraps can be reused in non-load bearing construction. 

Much processed lumber currently ends up as biomass fuel, and is not recycled back into wood 

products. This prevents the emission of methane from wood waste aerobically decomposing in 

landfills, and can replace the need for fossil fuels, but does not offer the benefit in reducing the 

impact of manufacturing of new wood products that recycling does.

As with carpet, recycling dimensional lumber requires source separation for clean, high-value feedstock, 

and thus requires participation from private C&D firms. This can be challenging for these firms, especially 

during demolition, when clean, reusable lumber and unrecyclable debris are often intermingled. 

Local and state governments can improve lumber recycling practices by establishing C&D recycling 

requirements, providing education and information about the recycling process and available 

markets, and by supporting innovation in C&D processes that improve recycling opportunities. 

For example, California’s new CalGreen statewide building code requires at least 50 percent 

construction materials diversion from each residential or commercial project.

47 Governments can also 

support market development of production of and demand for recycled wood products using locally 

recovered and processed dimensional lumber. Going beyond lumber recycling, governments can 

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promote deconstruction, an alternative method for building removal that preserves materials and 

encourages the reuse of wood products.

48

9bE 6%%).>"80;-

As mentioned previously, food scraps are a major source of methane emissions from landfills. 

Because food decomposes relatively quickly, food scraps often begin releasing methane before landfill 

methane collection systems can be installed. States can reap meaningful and direct emission 

reductions from alternative management of food scraps. Food scraps are the single largest volume of 

material, by weight, disposed in landfills in California, Oregon, and Washington. 

More than 90 towns and cities in the U.S. offer single-family residential food waste collection for 

composting and West Coast cities lead the pack.

49 Many of these communities also have commercial 

composting programs in place as well. Commercial sources can be used to initiate composting 

programs, as they offer large volumes of source-separated food, a model followed by San Francisco and 

other communities in California. Food scrap composting not only delivers emissions reductions, it 

offers potential cost savings as well. Seattle Public Utilities estimates that its program costs about 20% 

less per load than landfilling. In 2009, this translated into a savings of approximately $250,000.50

Compost produced by food scraps offers several additional benefits during its use, including reducing or 

eliminating the need for chemical fertilizers, improving soil porosity and water retention, facilitating 

reforestation and habitat restoration, and bioremediation, and promoting higher yields of agricultural 

crops. As mentioned above, the WARM emissions factor leaves out a number of benefits from 

composting, including emissions reductions from decreased water use, decreased soil erosion, and 

reduced fertilizer and herbicide use. If these components were included, as they are in the California Air 

Resources Board’s methodology, the emissions reduction potential of food scraps would be even

greater

51. ARB’s analysis estimates 0.42 MTCO2e reduction for every ton composted, without considering 

landfill methane avoidance. For further discussion of WARM and composting, see Appendix E. 

As discussed earlier, GHG emissions reductions can also be achieved by diverting food scraps to 

anaerobic digestion. The emissions reduction potential of anaerobic digestion is not presented here 

because it is not included in the WARM Calculator. On the West Coast, the East Bay Municipal Utility 

District is currently investigating the possibility of of anaerobically co-digesting food waste at its main 

wastewater treatment plant.52And, in Washington, Cedar Grove Composting is seeking a permit to use 

anaerobic digestion to convert food and yard scraps into biogas to produce electricity and natural gas.

53

Environment Canada commissioned an evaluation of the life-cycle GHG benefits of composting and 

anaerobic digestion, and found that if one considers the carbon storage benefits of compost, 

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composting is preferable to anaerobic digestion, although both reduce emissions relative to 

landfilling (given average Canadian conditions).54 Food anaerobic digestion operations can combine 

digestion with composting, taking advantage of the carbon storage role of compost and avoiding 

landfill disposal of digestion residuals. A proposed San Jose facility would combine dry fermentation 

anaerobic digestion with in-vessel composting.

55

However, compost facilities can be problematic if not operated optimally. This can lead to emissions 

of VOCs, as well as odor and vector issues, undermining community support. Best practices have 

been developed by the U.S. Composting Council under a grant from the EPA that suggest how to 

minimize odor and other potential issues through proper aeration, feedstock management, 

carbon/nitrogen balance and covering rows with finished compost.

56 However, in some regions, 

anaerobic digestion of food waste may be a better option.

57

Also, although not measured in the WARM Calculator, there are opportunities to “recycle” food by 

diverting what is discarded by grocery stores and commercial food service operations to food banks 

and soup kitchens. So-called “food rescue” programs exist in many communities for coordinating the 

collection and distribution of discarded pre-consumer food waste.

58 These programs deliver the 

benefits of waste prevention while providing a valuable resource to people in need.

Of course, as with all of the top ten materials, reducing the amount of food wasted overall delivers 

powerful emissions reductions as well. In a successful example from abroad, the UK’s “Love Food, 

Hate Waste” campaign, spearheaded by the British government, has engaged citizens with 

information and educational outreach on how to waste less food. Since its launch in 2009, the 

campaign estimates that it has reduced 2.8 million MTCO2e.

59

Estimates for the U.S. suggest that between 26% and 40% of all available food is wasted.

60 Preventing 

that waste is a huge opportunity for emissions reductions and cost savings for individuals and 

governments alike.

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The WARM results presented in this report provide policymakers and materials management 

professionals in California, Oregon, and Washington a good idea of which materials carry the greatest 

potential for emissions reduction if diverted from landfill disposal through recycling or composting. 

At a time when limited resources are available for meeting multiple urgent policy goals, programs 

that focus on diverting these priority material types from landfill disposal through recycling or 

composting can deliver emissions reductions and contribute to climate action goals, while producing 

other more widely accepted benefits such as resource conservation, cost savings, job creation and 

economic development.

Although recycling is an established practice in many West Coast communities, this report shows that 

further progress can be made, both to divert greater quantities of materials currently being recycled 

and to establish new programs for additional materials. For some materials, such as carpet and 

dimensional lumber, effective materials management strategies and mechanisms are relatively new 

or still being developed and more research and experimentation is needed to understand how 

communities can recycle these materials most effectively. Likewise, food scrap management offers 

new and rapidly evolving opportunities. Further research and evaluation of on-the-ground results 

will be important for helping communities determine how best to divert food scraps from landfills 

and reap the GHG emissions reductions benefits. Even best practices for core recyclables are 

undergoing change, such as a transition to single-stream collection and processing systems and 

expansion of mandatory recycling to the commercial sector. 

Meeting these opportunities will require expansion of processing, reuse, and manufacturing 

infrastructure. The West Coast is deficient in food composting and anaerobic digestion facilities,

although several composting and digestion facilities employing various technologies are either 

planned or under construction. Many traditional recycled materials are exported rather than utilized 

domestically at the same time that domestic recyclers are in need of more materials. While increasing 

diversion and recycling of more materials will generate more jobs domestically in the collection, 

transport, sorting and marketing areas, the material will need to be recycled domestically to have the 

greatest impact on job creation and economic activity. Reuse opportunities can also be expanded, 

especially for deconstructed building materials. 

These changes create challenges as well as opportunities, and necessitate continued innovation and 

improvements. The Materials Management Workgroup of the West Coast Climate and Materials

Management Forum is committed to continuing to provide research and information on current 

strategies and best practices in recycling and composting of these priority materials. 

A0,(850'-.A0$0*(+($,.^(?%$).=("?"'5$*.0$).3%+;%-,5$*

The analysis featured here estimates the emissions reduction potential of recycling and composting 

various materials versus depositing them in a landfill, but it does not provide a comprehensive 

comparison of other life-cycle materials management strategies, such as green purchasing, producer 

responsibility, product stewardship, and decreased consumption, except to the extent that these 

strategies might be used to achieve the recycling results simulated in the model’s recycling scenario.
!"#$%&'()*+""',-$.")*/.)01&..&-'.)2,+-$(,)!"%3%4&'()/'#)5-16-.2&'() 7:

The analysis also fails to capture the significant GHG emissions reduction that can be achieved 

through changes to materials management-related issues such as transportation modes, 

manufacturing practices, distribution infrastructure, energy sources, and product design. 

To fully understand the emissions reduction potential of sustainable materials management, the 

entire spectrum of strategies available across the entire life cycle of materials must be examined. The 

workgroup looks forward to the opportunity to focus on these strategies in future projects.
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The first emissions factor for carpet recycling (7.22 MTCO2e net emissions reduction) comes from 

the WARM Calculator and assumes an open loop recycling process. A number of industry and 

government stakeholders have expressed concerns with the assumptions used in the development in 

the emissions factor. Specifically, there are three major concerns:

1) The WARM factor was developed using data about the material composition of residential 

carpet, which is significantly different from commercial carpet. Because residential carpet 

makes up a minority of carpet in the waste stream (only 22% of carpet landfilled in California 

is from the residential sector, and only 10% in Washington is), the use of residential carpet 

data may be misleading. 

2) The WARM factor calculation assumes that carpet recycling is an “open loop” process, and 

that carpet is recycled in the following proportions: 67% is recycled into carpet pad, 25% is 

recycled into molded plastic parts, and 8% is recycled into carpet tile backing. These 

assumptions do not match the latest reports from the carpet industry about how carpet is 

recycled. According to the Carpet American Recovery Effort (CARE) 2009 Annual Report, 

carpet is recycled as follows: 45% is turned back into carpet, 33% is recycled into plastic 

pellets (used in plastic product manufacturing), 12% is recycled into carpet pad, 5% is 

recycled directly into molded plastic parts, 4% is recycled into other products, and 1% is used 

as engineered fuel. 

3) The WARM factor calculation assumes that the current mix of inputs for carpet 

manufacturing is 100% virgin materials. With 45% of all recycled carpet being recycled back 

into carpet, this is clearly not entirely accurate. However, as of 2009, only 4.2% of all postconsumer carpet is recycled, so it is likely that most carpet manufacturing includes little if 

any recycled content. 

The U.S. EPA is aware of the limitations and potential flaws in the WARM emissions factor for carpet 

recycling and is working with experts in the industry and academic community to revise these factors 

for future versions.

In the meantime, we have chosen to calculate the emissions reduction potential for carpet in two 

ways. First, we continue using the WARM emissions factor for consistency and because the 

assumptions and calculations are transparent and freely available for review and critique at 

http://www.epa.gov/climatechange/wycd/waste/downloads/carpet-chapter10-28-10.pdf.

Second, we use an emissions factor for closed loop carpet recycling (2.21MTCO2e net emissions 

reduction for carpet recycled back into carpet) developed by Dr. Jeffrey Morris of Sound Resource 

Management in a report to Seattle Public Utilities titled, “Environmental Impacts from Carpet 

Discards Management Methods: Preliminary Results.”

Because neither the assumptions used for WARM nor Dr. Morris’s analysis accurately reflect the 

nature of the carpet recycling market today, both emissions factors present skewed estimates of the 

emissions reduction potential of recycling carpet currently in the waste stream in WA, OR, and CA. 

Unfortunately, they represent the best estimates currently available for public use. We hope that by 

providing both in our analysis, we reflect the range of estimated emissions reduction potential for 

carpet recycling.
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From “Materials Management Approaches for State and Local Climate Protection”

http://captoolkit.wikispaces.com/WARM

EPA’s Waste Reduction Model (WARM) is a tool for assessing the GHG emissions of a baseline and 

an alternative waste management method for handling any of 32 materials and 8 mixed materials 

categories. It was created to help solid waste planners and organizations track and voluntarily repo rt 

GHG emissions reductions from several different waste management practices. WARM is publicly 

available both as a Web-based calculator and as a Microsoft Excel spreadsheet.

WARM calculates and totals GHG emissions of baseline and alternative waste management practices 

(i.e. landfilling, incineration, source reduction, recycling, and composting). The model calculates 

emissions in metric tons of carbon equivalent (MTCE), metric tons of carbon dioxide equivalent 

(MTCO2E), and energy units (million BTU) across 40 material types commonly found in municipal 

solid waste (MSW). The emission factors represent the GHG emissions associated with managing 1 

short ton of MSW in a specified manner. GHG savings must be calculated by comparing the emissions 

associated with the alternative scenario with the emissions associated with the baseline scenario. 

Without the comparison, part of the emissions savings or cost will be excluded.

The model takes a life cycle view and incorporates in the emissions factors for each material the 

emissions from raw materials acquisition, processing, manufacturing, transportation, and end-of-life 

management. However, the use phase of materials is not considered in the model’s calculations. For 

most materials, recycling is modeled as a closed-loop. For example, a plastic PET bottle is recycled 

into a plastic PET bottle. For those materials where there is not a dominant use of a recycled material 

or a lack of data, an open-looped process may be modeled. Open-loops are common for many of the 

paper-based material categories. Details for what is and isn’t included can be found in the FAQ.

(http://www.epa.gov/climatechange/wycd/waste/calculators/WARM_faq.html )

WARM is widely used by national, state, and local governments. Because it is commonly used, it 

lends some universality and comparability to the analyses that are done with it. It is a “common 

denominator” for solid waste GHG emissions in the US. Other available tools sometimes have 

drawbacks that WARM does not; they may be proprietary and accessed only through contract, may 

carry costs for use, and may not be as widely used.

Although it remains one of the best options available for state and local governments to estimate the 

emissions reduction potential of recycling, composting, and source reduction (relative to incineration

and landfilling), WARM is not without limitations. Here are some that have implications for this report:

R!=A.0$).A0,(850'-.30,(*%85(-.

WARM users face the challenge of reconciling their own materials category definitions with those the 

model employs. WARM’s categories for mixed paper and corrugated cardboard remain ambiguous 

since there are a many materials with different emissions impacts that would fall into these 

categories in varying ratios. 
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WARM focuses on materials, not products, which leaves out some significant pieces of the solid waste 

stream. It doesn’t, for example, include such categories as sheetrock, textiles (which can have 

multiple materials in products) or household items – furniture, toys, sporting goods, electronics 

other than PCs. Material list is found on the WARM homepage: 

http://www.epa.gov/climatechange/wycd/waste/calculators/Warm_home.html

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 Some materials management efforts are better evaluated using other methods and tools. WARM is 

not easily adapted to comprehensive comparisons of materials management strategies such as 

product stewardship, EPP or reuse programs. For example, the lack of “upstream” (or productionrelated) emissions for food limits WARM’s utility for evaluating food waste prevention projects. Also, 

WARM currently has no capacity to calculate reuse separate from source reduction. The source 

reduction management option assumes materials not manufactured. Using the source reduction 

calculations as a proxy for reuse activities only works if one assumes that the reuse actually 

substitutes for the mining and manufacture of virgin materials that would have otherwise been 

necessary. This is a shaky assumption, since some reuse activities don’t actually displace production 

of new materials.

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GWP is a concept designed to compare the ability of a greenhouse gas to trap heat in the atmosphere 

relative to another gas. The definition of a GWP for a particular greenhouse gas is the ratio of heat 

trapped by one unit mass of the greenhouse gas to that of one unit mass of CO2 over a specified time 

period. WARM uses 21 as the GWP for methane, which is the 100 year GWP listed in the IPCC’s 

second assessment from 1996. According to the EPA, November 2009, this will not be changed 

anytime soon as the GWP is set by the United Nations Framework Convention on Climate Change 

(UNFCCC) which EPA must use for national GHG inventories (and which is based on the IPCC 

second assessment). It is important to note that the more recent IPCC Assessment 4 (2007) uses a 

100 year GWP for methane of 25. However, many state and local inventory and waste professionals 

believe that using a 20 year horizon GWP of 72 for methane highlights the potential for important 

short-term emissions reduction benefits, since methane decays quickly (it has a 12 year lifetime) and 

thus has its maximum warming impact well before 100 years is reached. 

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As of August 2010, a new version of WARM includes a more comprehensive analysis of composting 

yard and food waste than it has in the past. First, the calculation of landfill emissions from organics is 

based on a first-order decay rate to better measure when emissions are generated. Previous versions 

of the model only calculated the lifetime methane yield. In addition, landfill gas capture systems is 

modeled with a time element, assuming systems are phased in at landfills. With these two new 

elements, the model is able to estimate the amount of methane being generated at a particular time 

and the amount of methane being captured at that time. This new calculation methodology most 

affects food waste and grass. 
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The emission factors for branches, which degrade at a very slow rate, changed very little. The new 

emission factor takes into account the higher soil carbon sequestration capacity for compostimproved soil as well as the GHG emissions involved in composting machinery and transportation.

However, the updated model still does not include an emission factor for other compostable 

materials, like non-recyclable paper. WARM also does not include GHG emissions or emissions 

reductions associated with other co-benefits associated with the use of compost, such as water 

conservation and changes in fertilizer use. Finally, WARM does not differentiate between the 

potential for varying emissions from compost sites themselves as a function of technology (e.g., 

anaerobic vs. aerobic composting, or centralized vs. home composting).

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WARM does not currently break emissions and emissions reductions into the years in which they 

actually occur. Rather, WARM rolls all future emissions and emissions reductions into a single 

number. While appropriate for comparing program options against each other, this limits WARM’s 

usefulness in inventories, since most other emissions are reported in the years in which they actually 

occur. Organic materials (e.g. cardboard, paper, lumber) have avoided emissions associated with 

source reduction and recycling that are time-sensitive. 

Forest carbon sequestration: When paper is recycled, fewer trees are cut down. This carbon 

sequestration reduces the net emissions associated with paper source reduction and recycling. The 

reductions occur over decades, since every year following the actual recycling or source reduction 

event, over their lifetime, these trees absorb carbon as they continue to grow. 

Avoided landfill emissions: When paper is recycled, less of it goes into the landfill. Landfill methane 

emissions are reduced, and these avoided emissions reduce the net emissions associated with paper 

source reduction and recycling. These reductions occur over decades, since decay in the landfill 

occurs over decades. The same is true for diversion of other putrescible wastes, such as food waste 

composting. 

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WARM treats international production – both of virgin and recycled materials – as if production in 

other countries have the same emissions factors (emissions per ton) as domestic production. Given 

the international flow of products and recycled feedstocks, and the potential for significant regional 

differences in emissions based on regional fuel mixes and technology patterns, this is a potential 

limitation. This is particularly acute in the forest carbon sequestration element of WARM (for paper 

recycling and source reduction), which is based entirely on modeling of forest management practices 

in the domestic US. Forest management practices, and the associated carbon benefits/impacts of 

reducing use of wood, likely vary widely between the US and some other areas of the world, including 

areas that would supply virgin fiber to foreign mills were it not for their use of wastepaper exported 

from the US.