Evidence Rating  
Evidence rating: Scientifically Supported

Strategies with this rating are most likely to make a difference. These strategies have been tested in many robust studies with consistently positive results.

Disparity Rating  
Disparity rating: Potential to decrease disparities

Strategies with this rating have the potential to decrease or eliminate disparities between subgroups. Rating is suggested by evidence, expert opinion or strategy design.

Health Factors  
Date last updated

Composting uses an aerobic, natural decomposition process to turn food and yard waste into nutrient-rich soil amendments. Composting can be done at the individual level with a backyard bin or tumbler or with an indoor or outdoor vermicomposting (worm composting) system1, 2. Community composting can be scaled and designed for cities, towns, neighborhoods, or other groups through nonprofits, small businesses, local farms, community gardens, and other organizational models3. Large, commercial scale composting operations reach higher temperatures than home composting bins, so they can break down organic waste such as compostable bioplastics that home composting cannot2. Composting is a key component of a circular economy that sustainably manages the food system, avoids wasting food that could be donated, and food waste (i.e. plate waste that was served but not consumed, spoiled food, or inedible produce trimmings, rinds, or peels) that could be composted instead of sent to a landfill4. Agricultural waste, crop residue, and unharvested crops, as well as food loss through the food retail system can also be composted4. About one-third of food around the world is wasted5, 6.

The evidence reviewed in this strategy is primarily focused on composting food scraps and plant waste, rather than composting operations that deal with agricultural and industrial waste, manure, sewage sludge, organic municipal solid waste, and other biodegradable wastes. This strategy also evaluates aerobic composting rather than anaerobic composting, a process where organic matter decomposes without the presence of oxygen and produces methane gas.

What could this strategy improve?

Expected Benefits

Our evidence rating is based on the likelihood of achieving these outcomes:

  • Improved soil health

  • Increased carbon sequestration

  • Reduced emissions

Potential Benefits

Our evidence rating is not based on these outcomes, but these benefits may also be possible:

  • Reduced run-off

What does the research say about effectiveness?

There is strong evidence that composting food waste improves soil health7, 8, 9, 10, 11, 12, increases soil carbon content and carbon sequestration7, 13, 14, and reduces emissions, especially by averting methane emissions from landfills15, 16, 17, 18.

Composting improves soil fertility, microbial and enzymatic activity, nutrient content, and physical properties, including density and porosity7, 8, 11, 12, 15. Composting can reduce soil erosion, eutrophication of waterways15, soil contaminants, pathogens, and plant diseases7, 8, 9, 12, 19. Applications of compost and other soil amendments can help reclaim salt-affected soils and return degraded soils to productive agricultural use20. High-quality compost can remediate soils contaminated with microplastic pollution, heavy metals, and other hazardous pollutants, meaning the microbial process of composting can breakdown some micropollutants and reduce the availability, mobility, and ecological risk of other hazards in the soil21, 22. Vermicomposting and using soil amendment additives can increase the effectiveness of compost remediation13, 21, 22. Sorting food waste from other municipal solid waste at the collection point, rather than mechanically separating it after collection, prevents increasing microplastic, heavy metal, and other contamination in the food waste prior to composting21, 22.

Composting increases carbon and nitrogen conservation in the soil, preventing carbon and nitrogen from accumulating in the atmosphere as greenhouse gases, especially carbon dioxide and nitrous oxides13, 14, 15, 18. Composting increases soil’s water retention and decreases run-off, which improves carbon sequestration, plant health12, 14, and crop productivity7. Composting supports plant growth and increases carbon dioxide uptake and storage within plants18. Available evidence shows that composting to reduce food waste has the potential to provide large scale reductions to atmospheric carbon5, 23, 24. Organic farming practices use composting and have been shown to increase soil carbon and provide higher carbon sequestration than conventional farming23, 25. Organic farming practices including composting are also a suggested strategy for adaptation to climate change, since they are more resilient, more efficient with water use, and provide higher yields in drought years than conventional farming practices23.

Composting avoids methane gas production that is generated in landfills during anaerobic decomposition, and analysis shows this is especially beneficial for food scraps16, 17. By improving soil physical structure, compost makes the soil more workable, which can further reduce emissions by reducing fossil fuel use to work the soil18. Applying compost to soil reduces fertilizer and herbicide use15, which further reduces greenhouse gas emissions from the production and application of those fertilizers and pesticides18. Source separation of municipal solid waste requires heavy machinery to separate, grind, mix, and aerate compostable materials, which requires energy and produces greenhouse gas emissions18. Sorting compostable food and yard waste before collection reduces these issues and produces a higher quality compost product without contamination from contact with other waste26.

Vermicomposting can provide even greater benefits than traditional aerobic composting, with a faster process, more nutrient-rich final product, greater effects on disease suppression27, and increased removal of heavy metals and toxic substances28. Vermicomposting can also be adapted for use on the biodegradable portion of municipal solid waste, including food, paper, and green waste29 and vermicomposting of municipal solid waste reduces bacteria and pathogen loads from final compost product30.

Composting efforts in urban areas can improve soil health and increase soil carbon storage10, 13. Composting improves physical properties of degraded, compacted urban soil such as bulk density and water infiltration, which reduces run-off and erosion, and makes it easier for plants to grow10. Composting to improve soil health in urban areas provides many co-benefits, including increasing urban green space, which can reduce heat island effects and improve mental health; improving urban gardening, which can improve local food security and food quality; supporting productive and sustainable community gardens; and remediating soil by reducing the availability of lead, arsenic, and other contaminants in the soil for plants to absorb13. Additional research is needed on compost application rates, depth of incorporation, and concentrations to achieve the greatest improvements in urban soil physical properties10.

Compost quality is affected by the waste source, raw materials used, and variables during the composting process31. Implementing a system to sort and collect food waste for compost that is separate from municipal solid waste can prevent heavy metal and toxic substance contamination and reduce the need for waste pretreatment and subsequent odors and bioaerosols26, 32. Ensuring compost maturity and stability prior to soil application increases benefits to soil quality, improves stable carbon storage, and improves plant health benefits11, 31. Using physical, chemical, and microbial additives, increasing aeration, and using pretreatment processes while composting can improve nitrogen retention and reduce soil nitrous oxide emissions, though these efforts are more necessary for municipal solid waste composting than pre-sorted food waste composting33, 34. Composting benefits can be maximized with site specific application strategies that account for past land use, current conditions, and future uses14. Composting can be time consuming and compost practices need to monitor compost piles to ensure that food waste addition does not create overly wet conditions that can lead to anaerobic decomposition that produces methane. The use of brown leaves or yard waste, shredded paper, bulking agents, and other additives can improve structure to facilitate oxygen incorporation and can improve nitrogen and carbon balance to prevent anaerobic decomposition8.

Composting can be implemented effectively at almost any scale, from home composting to large city-wide treatment facilities11. Experts calculate that composting costs less than landfill waste disposal for food waste. The cost of establishing new composting facilities is less than the cost of establishing new landfills, and though operating costs for large scale compost facilities are higher than those for landfills, composting also generates revenue with the sale of the finished product. Regulations, space, and logistic constraints can increase the costs of landfill expansion, which makes composting even more cost effective24. Home composting is inexpensive to establish, requires minimal equipment, and can improve home or community gardens and save money that would have been spent on fertilizers and pesticides1. In the U.S. developing a circular economy to sustainably manage food throughout its life cycle at the production, processing, transportation, consumption, and waste stages can conserve resources, save money, and improve food access4.

Life cycle analysis suggests composting provides more environmental benefits and climate change impact reductions than other organic waste disposal methods such as sending waste to the landfill or waste-to-energy projects15.

How could this strategy advance health equity? This strategy is rated potential to decrease disparities: suggested by expert opinion.

Experts suggest composting has the potential to decrease disparities in exposure to landfill waste and public health outcomes between those with lower incomes and those with higher incomes and to support environmental justice in communities with fewer resources experiencing disinvestment and overburdened by environmental hazards2, 60, 61. Available data shows waste management facilities including landfills, waste incinerators, and legal and illegal hazardous waste sites, are disproportionately located in communities with more residents of color and people with low incomes62. Conventional waste management practices disproportionately impact the well-being and health of communities of color with low incomes62. Experts suggest composting initiatives can change and improve equity in waste management, food systems, environmental exposures, and climate change effects using community participation to develop local collection, composting, and distribution systems61.

Experts recommend integrating food and waste justice initiatives to create equitable policies and contracts for all communities63. Case studies suggest communities have inequitable access to mature, high-quality compost63. Many urban communities would benefit from community composting and city compost services, especially if the compost is sourced from food waste, that was picked up separately, tested, and delivered to community gardens and public green spaces63, 64. Such systems could improve the safety and equity of organic waste-to-compost cycles63. Experts suggest high-quality compost would be especially beneficial if provided to community gardens and urban agriculture initiatives that serve people with low incomes, experiencing food insecurity, and working in neighborhoods with soil that needs revitalization and remediation63. Local and state legislation can support sharing safe, nutrient-rich compost in structurally disadvantaged communities63.

A Baltimore case study suggests local composting can be used to support local tree planting initiatives to reduce urban heat island effects that disproportionately impact formerly redlined neighborhoods with residents of color and with lower incomes64.

What is the relevant historical background?

Composting has always been a part of nature’s waste disposal system and since the beginning of human history there is evidence that many societies have valued compost as a fertilizer65, 66. In the early 1900s, however, companies began to produce chemical fertilizers that almost entirely replaced compost. By 1950, estimates suggest that 99% of the fertilizer used in the U.S. was from chemicals instead of compost66. Compost was minimally used until the 1960s, when an era of increased environmental consciousness made organic farming and composting more popular66. In the 1980s, recognition that the U.S. was generating too much waste increased interest in recycling, yard waste composting, and environmental laws to regulate industrial waste disposal and to protect humans and wildlife from chemical fertilizers and pesticides, which increased composting efforts in many industries and among many farmers66.

The U.S. generated close to 300 million tons of municipal solid waste in 201867. Of that only 25 million tons were composted, which included 22.3 million tons of yard waste and 2.6 million tons of food waste67. According to the U.S. Environmental Protection Agency (U.S. EPA), almost 25% of all municipal solid waste is food waste. Over 51% of municipal solid waste sent to landfills is compostable, including yard waste and biodegradable wood, paper, and cardboard68. The U.S. EPA estimates over 66 million tons of food was wasted in 2019 in food retail, food service, and homes, and only 5% of that food waste was composted68.

Equity Considerations
  • Which neighborhoods in your community do not have composting services or access to high-quality compost for public or private gardening or greening initiatives?
  • What infrastructure, services, tools, or educational resources are needed to help your local community develop or increase participation in composting programs?
  • How can your community composting services support local needs for soil remediation, reducing run-off, greening initiatives, gardening, urban agriculture, or climate change mitigation and adaptation? What outreach activities could raise awareness about composting benefits and composting opportunities, to increase participation?
  • Who makes decisions about composting services in your community? How is your community engaging residents and stakeholders from neighborhoods experiencing environmental injustice and disproportionate burdens from society’s waste system to develop and plan composting initiatives that change the current food and waste systems?
Implementation Examples

California35, Connecticut36, Maryland37, Massachusetts38, New Jersey39, 40, New York41, Rhode Island42, Vermont43, and Washington44 are the nine states with laws that regulate sending organic waste to composting facilities instead of to landfills45. Several states have grants available to support additional composting efforts; for example, the Maryland State Department of Education has grants for schools starting food waste reduction and composting programs46 and the California Department of Resources Recycling and Recovery offers grants for small-scale composting projects for green spaces in disadvantaged communities47. The U.S. Composting Council is a national organization with 16 state chapters that support compost manufacturing and use for the benefits it provides to soil, air, and water quality, and to climate stabilization48. The U.S. Composting Council also offers a searchable database of state regulators and regulations that affect composting efforts49.

Several cities in the U.S. have successful, mandatory composting programs, including San Francisco50; Portland, Oregon51; Boulder and Denver, Colorado52, 53; and Seattle54. San Francisco was the first U.S. city to establish a city-wide composting program in 1996 and currently composts and recycles roughly 80% of its waste55. Many cities are implementing composting pilot programs, including Boston, Pittsburgh, and Jacksonville, Florida45. New York City has also passed a new Zero Waste Act that includes mandatory composting programs with curbside pickup, universal composting for all residential buildings, increased organic waste drop off locations, and expanded compost facilities increasing equitable access to composting across the five boroughs56.

At the federal level, grants are available that support initiatives to reduce food waste and increase composting opportunities, for example, the U.S. Department of Agriculture’s Composting and Food Waste Reduction Cooperative Agreements help local and city governments develop and implement community composting plans57. The Inflation Reduction Act of 2022 includes Greenhouse Gas Air Pollution Plans and Implementation Grants and the U.S. Environmental Protection Agency administers the Solid Waste Infrastructure for Recycling Grant Program; both grant programs can support composting initiatives58.

Composting initiatives are operated by many non-profit organizations across the country. For example, Conservation Works operates the Waste Wizards program in Northern California that teaches children about composting and reducing food waste to reduce climate change effects and diverts food waste from school cafeterias to create compost59. Many community composting projects are equity-focused initiatives; for example, the Baltimore Compost Collective. This project is located on an acre of land in the Curtis Bay neighborhood that has experienced environmental injustice. The land was once polluted and now is home to a healthy community garden with 47 individual plots, beehives, goats, and ducks. The Baltimore Compost Collective is also building the nation’s largest municipally-managed compost facility and using composting to support environmental justice in disadvantaged neighborhoods, offer job training for youth, and reduce greenhouse gas emissions60.

Implementation Resources

Resources with a focus on equity.

US EPA-Composting - U.S. Environmental Protection Agency (US EPA). Composting at home.

ZFWC-State policy toolkit 2023 - Zero Food Waste Coalition (ZFWC). Achieving zero food waste: A state policy toolkit. May 2023.

Project Drawdown-Composting - Project Drawdown. Climate solutions: Composting.

Project Drawdown-Reg Ag - Project Drawdown. Climate solutions: Regenerative annual cropping.

ILSR-Composting podcast - Institute for Local Self-Reliance (ILSR). Composting for community podcast.

FWA-Compost resources - Food Well Alliance (FWA). Compost resources list and resource guide.

USDA-Composting - U.S. Department of Agriculture (USDA). Composting.

NRDC-Hu 2020 - Hu S. Composting 101. National Resources Defense Council (NRDC). 2020.

NRDC-Mugica 2019 - Mugica Y, Rose T. Tackling food waste in cities: A policy and program toolkit. National Resources Defense Council (NRDC), The Rockefeller Foundation. 2019.


* Journal subscription may be required for access.

1 US EPA-Composting - U.S. Environmental Protection Agency (US EPA). Composting at home.

2 Yale-Silver 2022 - Silver W, Abott-Lum F. Yale experts explain composting. Yale Sustainability. 2022.

3 US EPA-CC - U.S. Environmental Protection Agency (US EPA). Community composting (CC).

4 US EPA-Food management - U.S. Environmental Protection Agency (U.S. EPA). Sustainable management of food basics.

5 Project Drawdown-Food waste - Project Drawdown. Climate solutions: Reduced food waste.

6 FAO-Food waste - Food and Agriculture Organization of the United Nations (FAO). Food wastage footprint & climate change.

7 Brichi 2023 - Brichi L, Fernandes JVM, Silva BM, et al. Organic residues and their impact on soil health, crop production and sustainable agriculture: A review including bibliographic analysis. Soil Use and Management. 2023;39(2):686-706.

8 Palansooriya 2023 - Palansooriya KN, Dissanayake PD, Igalavithana AD, et al. Converting food waste into soil amendments for improving soil sustainability and crop productivity: A review. Science of the Total Environment. 2023;881:163311.

9 Thakur 2022 - Thakur R, Verma S, Gupta S, Negi G, Bhardwaj P. Role of soil health in plant disease management: A review. Agricultural Reviews. 2022;43(1):70-76.

10 Kranz 2020 - Kranz CN, McLaughlin RA, Johnson A, Miller G, Heitman JL. The effects of compost incorporation on soil physical properties in urban soils – A concise review. Journal of Environmental Management. 2020;261:110209.

11 Sayara 2020 - Sayara T, Basheer-Salimia R, Hawamde F, Sánchez A. Recycling of organic wastes through composting: Process performance and compost application in agriculture. Agronomy. 2020;10(11):1838.

12 De Corato 2020 - De Corato U. Agricultural waste recycling in horticultural intensive farming systems by on-farm composting and compost-based tea application improves soil quality and plant health: A review under the perspective of a circular economy. Science of the Total Environment. 2020;738:139840.

13 Malone 2023 - Malone Z, Berhe AA, Ryals R. Impacts of organic matter amendments on urban soil carbon and soil quality: A meta-analysis. Journal of Cleaner Production. 2023;419:138148.

14 Gravuer 2019 - Gravuer K, Gennet S, Throop HL. Organic amendment additions to rangelands: A meta-analysis of multiple ecosystem outcomes. Global Change Biology. 2019;25(3):1152-1170.

15 Huang 2022 - Huang D, Gao L, Cheng M, et al. Carbon and N conservation during composting: A review. Science of the Total Environment. 2022;840:156355.

16 Mckenzie 2022 - Mckenzie I, Diana S, Jaikishun S, Ansari A. Comparative review of aerobic and anaerobic composting for the reduction of organic waste. Agricultural Reviews. 2022;43(2):234-238.

17 Brown 2016b - Brown S. Greenhouse gas accounting for landfill diversion of food scraps and yard waste. Compost Science and Utilization. 2016;24(1):11-19.

18 Lou 2009 - Lou XF, Nair J. The impact of landfilling and composting on greenhouse gas emissions - A review. Bioresource Technology. 2009;100(16):3792-3798.

19 De Corato 2020a - De Corato U. Disease-suppressive compost enhances natural soil suppressiveness against soil-borne plant pathogens: A critical review. Rhizosphere. 2020;13:100192.

20 Leogrande 2019 - Leogrande R, Vitti C. Use of organic amendments to reclaim saline and sodic soils: A review. 2019;33(1):1-21.

21 Le 2023 - Le VR, Nguyen MK, Nguyen HL, et al. Organic composts as a vehicle for the entry of microplastics into the environment: A comprehensive review. Science of the Total Environment. 2023;892:164758.

22 Huang 2016a - Huang M, Zhu Y, Li Z, et al. Compost as a soil amendment to remediate heavy metal-contaminated agricultural soil: Mechanisms, efficacy, problems, and strategies. Water, Air, and Soil Pollution. 2016;227:359.

23 Leu 2014 - Leu A. The potential for mitigation and adaptation to climate change with soil organic matter increases in organic production systems. Acta Horticulturae. 2014;1018:75-82.

24 Project Drawdown-Composting - Project Drawdown. Climate solutions: Composting.

25 Gattinger 2012 - Gattinger A, Muller A, Haeni M, et al. Enhanced top soil carbon stocks under organic farming. Proceedings of the National Academy of Sciences of the United States of America. 2012;109(44):18226-18231.

26 Cerda 2018 - Cerda A, Artola A, Font X, et al. Composting of food wastes: Status and challenges. Bioresource Technology. 2018;248:57-67.

27 Yatoo 2021 - Yatoo AM, Ali MN, Baba ZA, Hassan B. Sustainable management of diseases and pests in crops by vermicompost and vermicompost tea. A review. Agronomy for Sustainable Development. 2021;41:7.

28 Mohee 2014 - Mohee R, Soobhany N. Comparison of heavy metals content in compost against vermicompost of organic solid waste: Past and present. Resources, Conservation and Recycling. 2014;92:206-213.

29 Ducasse 2022 - Ducasse V, Capowiez Y, Peigné J. Vermicomposting of municipal solid waste as a possible lever for the development of sustainable agriculture. A review. Agronomy for Sustainable Development. 2022;42:89.

30 Soobhany 2017 - Soobhany N, Mohee R, Garg VK. Inactivation of bacterial pathogenic load in compost against vermicompost of organic solid waste aiming to achieve sanitation goals: A review. Waste Management. 2017;64:51-62.

31 Azim 2018 - Azim K, Soudi B, Boukhari S, et al. Composting parameters and compost quality: A literature review. Organic Agriculture. 2018;8:141-158.

32 Wei 2017 - Wei Y, Li J, Shi D, et al. Environmental challenges impeding the composting of biodegradable municipal solid waste: A critical review. Resources, Conservation and Recycling. 2017;122:51-65.

33 Shan 2021 - Shan G, Li W, Gao Y, Tan W, Xi B. Additives for reducing nitrogen loss during composting: A review. Journal of Cleaner Production. 2021;307:127308.

34 Wang 2018c - Wang S, Zeng Y. Ammonia emission mitigation in food waste composting: A review. Bioresource Technology. 2018;248:13-19.

35 CA-Organic waste - State of California, CalRecycle. New statewide mandatory organic waste collection.

36 CT DEEP-Composting - Connecticut Department of Energy & Environmental Protection (CT DEEP). Composting and organics recycling.

37 MD DOE-Composting - Maryland Department of the Environment (MD DOE). Organics diversion and composting.

38 MA DEP-Composting - Massachusetts Department of Environmental Protection (MA DEP). Composting & organics.

39 NJ DEP-Sustainable waste - State of New Jersey, Department of Environmental Protection (NJ DEP), Division of Sustainable Waste Management. Food waste recycling and food waste-to-energy production law.

40 NJCC - New Jersey Composting Council (NJCC). Compost climate change connection and food waste recycling law.

41 NY DEC-Composting - New York State Department of Environmental Conservation (NY DEC). Composting.

42 RIRRC-State laws - Rhode Island Resource Recovery Corporation (RIRRC). State waste & recycling laws.

43 VT DEC-Food scraps - Vermont Agency of Natural Resources, Department of Environmental Conservation (VT DEC). Food scraps.

44 WA DEE-Organics management - State of Washington Department of Ecology (WA DOE). Organics & food waste: Organics management law.

45 Vasilogambros 2023 - Vasilogambros M. Save your food scraps, save the Earth: More cities and states look into composting. New Hampshire Bulletin. June 22, 2023.

46 MD ED-School composting - Maryland State Department of Education (MD ED). School waste reduction and composting program.

47 CalRecycle-Compost grants - California Department of Resources Recycling and Recovery (CalRecycle). California climate investments: Community composting for green spaces grant.

48 US CC - U.S. Composting Council (U.S. CC). The voice of the compost industry.

49 US CC-State database - U.S. Composting Council (U.S. CC). State regulators and regulations: Searchable state database.

50 SFE-Composting - San Francisco Environment Department (SFE). Recycling and composting in San Francisco: FAQs.

51 Portland-Compost - City of Portland, Oregon. Garbage, recycling, and compost: History of Portland's garbage and recycling system.

52 Boulder-Zero waste - City of Boulder, Colorado. Universal zero waste ordinance.

53 Denver-Zero waste - City of Denver, Colorado. Zero waste: Recycle, compost, and trash.

54 Seattle-Food waste - City of Seattle, Washington, Seattle Public Utilities. Food waste requirements.

55 GM-Rosenberg 2020 - Rosenberg L. These are the biggest composting cities in the U.S. Green Matters (GM). November 17, 2020.

56 NYCC-Zero waste 2023 - New York City Council (NYCC). City Council Sanitation Chair Sandy Nurse, council members Shahana Hanif and Keith Powers pass the landmark Zero Waste Act. June 8, 2023.

57 USDA-CFWR - U.S. Department of Agriculture (USDA). Composting and Food Waste Reduction (CFWR) cooperative agreements.

58 ZFWC-State policy toolkit 2023 - Zero Food Waste Coalition (ZFWC). Achieving zero food waste: A state policy toolkit. May 2023.

59 CW-Food waste - Conservation Works (CW). Using nature-based solutions to reduce greenhouse gas emissions and increase resilience: Conservation Works climate change & fire resiliency activities: Addressing food waste.

60 TRF-Hamilton 2023 - Hamilton M. Grantee impact story: Composting for the climate and environmental justice. The Rockefeller Foundation (TRF). 2023.

61 ILSR-Brolis 2022 - Brolis LB. Composting for community podcast: Catalyzing greater equity through composting. Institute for Local Self-Reliance (ILSR). September 19, 2022.

62 Martuzzi 2010 - Martuzzi M, Mitis F, Forastiere F. Inequalities, inequities, environmental justice in waste management and health. European Journal of Public Health. 2010;20(1):21-26.

63 Hall 2023 - Hall J, Khanjar N, Seyoum G, et al. 20 years of environmental injustice and the Mississippi hog industry: Spatial and statistical analyses for low-wealth communities and communities of color. Environmental Justice. 2023.

64 BioCycle-Sierra 2022 - Sierra A, Hosain S. Local composting integral to reducing urban heat island impacts. BioCycle. September 13, 2022.

65 Larum 2022 - Larum D. How old is composting: Learn about the origins of composting. Gardening Know How. 2022.

66 TO-Compost 2015 - Texas Organics. The history of compost. 2015.

67 US EPA-National overview - U.S. Environmental Protection Agency (U.S. EPA). National overview: Facts and figures on materials, wastes, and recycling: Composting or other food management.

68 US EPA-SMF - U.S. Environmental Protection Agency (U.S. EPA). Sustainable management of food: Composting.