California Department of Resources Recycling and Recovery (CalRecycle)

Waste Prevention World

Glossary of  Waste Prevention Terms

This page seeks to shed some light on the many different terms used in describing the many important functions and aspects of waste prevention.

Waste Prevention Terms



Waste Prevention Terms

Composting--The biological decomposition of organic materials such as leaves, grass clippings, brush, and food waste into a soil amendment.  Composting is a form of recycling. The CalRecycle Organic Materials Management Web site addresses many aspects of composting.

Electronic Waste--Sometimes called E-Waste. A term loosely applied to consumer and business electronic equipment that is near or at the end of its useful life. There is no clear definition for e-waste.  It includes, computers, computer peripherals, telephones, answering machines, radios, stereo equipment, tape players/recorders, phonographs, video cassette players/recorders, compact disc players/recorders, calculators, and some appliances.  However, whether or not items like microwave ovens and other similar "appliances" should be grouped into the category has not been established. Certain components of some electronic products contain materials that render them hazardous, depending on their condition and density. For instance, California law currently views nonfunctioning CRTs (cathode ray tubes) from televisions and monitors as hazardous. Therefore, nonfunctioning CRTs from televisions and monitors are banned from the trash.  See the Electronics portion of this Web site for a description of Electronic waste.

Extremely Hazardous Waste--A subset of Hazardous Waste. Extremely hazardous waste is any hazardous waste or mixture of hazardous wastes which, if human exposure should occur, may likely result in death, disabling personal injury or serious illness caused by the hazardous waste or mixture of hazardous wastes because of its quantity, concentration, or chemical characteristics.

Grasscycling--The practice of leaving clippings on the lawn while mowing. For more information, see the CalRecycle grasscycling page.

Green Building--The practice of creating buildings that are designed, built, renovated, operated, or reused in an ecological and resource-efficient manner. Also known as sustainable building. Green building includes the practices of salvaging material from building demolition for reuse in new buildings and for recycling. The term, green building, is also applied to buildings that minimize impact to the environment, protect health and enhance productivity of occupants, and utilize energy, water, and other resources efficiently.

Hazardous Waste--Speaking in general terms, hazardous wastes are solid wastes that are toxic, ignitable, reactive, or corrosive according to Chapter 11 of Division 4.5 of Title 22 of the California Code of Regulations.  Other wastes can be categorically, or specifically included or excluded from the definition of hazardous waste. For a more complete definition refer to Title 22 or contact the Department of Toxic Substances Control. Hazardous waste is defined in section 66261.3 of division 4.5 of title 22 of the California Code of Regulations. Hazardous waste includes extremely hazardous waste, acutely hazardous waste, RCRA hazardous waste, non-RCRA hazardous waste and special waste.

Integrated Waste Management--Managing waste by multiple techniques to achieve solid waste and resource conservation goals. The techniques may include waste reduction, reuse, recycling, composting, transformation, disposal to landfills, and other means.

Medical Waste--In general, medical waste is waste which is generated or produced as a result of diagnosis, treatment, or immunization of human beings or animals, is biohazardous according to Section 117635 of the California Health and Safety Code, is generated by biohazardous research, is generated by the production or testing of biologicals including serums, vaccines, antigens, and anti-toxins, or is considered to be sharps waste. For a more complete definition, see Section 117690 of the California Health and Safety Code. You may also want to visit our page on health care waste at home.

Mercury--A toxic metal that can cause harm to people and animals including nerve damage and birth defects. Liquid mercury that is exposed to the air evaporates readily at room temperature. If mercury is released into the environment, it can contaminate the air we breathe and enter streams, rivers, and the ocean, where it can contaminate fish that people eat.

Pollution Prevention--Preventing all forms of pollution, including toxics and other pollutants emitted into air, water, and land. Waste prevention is a type of pollution prevention.

Postconsumer Content--Also known as postconsumer waste, any product which has served its intended use by a business or a consumer, which has been disposed and subsequently separated from solid waste for use as a constituent in a new product.

Postmanufacture Content--Also known as postmanufacture waste, waste that is created by a manufacturing process, and that is subsequently only used as a constituent in another manufacturing process.

Precycling--This is not a widely used or accepted term, but it refers to actions such as making purchasing decisions that will reduce waste such as buying goods with less packaging (e.g., goods in bulk or concentrated form), choosing products that will last longer, and avoiding single-use or disposable products. These actions are also considered to be waste prevention.

RCRA--The Resource Conservation and Recovery Act of 1976.  RCRA is a federal law that is the root of most federal and state hazardous waste management law in the United States, although California and a few other states were already regulating hazardous substances, including hazardous waste, before RCRA.  RCRA also set forth a framework for the management of non-hazardous wastes, although many states, including California, already managed non-hazardous solid wastes in a manner very similar to that framework.  For California the main benefit of RCRA was the establishment of a national cradle-to-grave tracking system for hazardous waste transport and disposal. For details on RCRA see U.S. EPA's description of federal laws and regulations.

Recycling--Using waste as material to manufacture a new product. Recycling involves altering the physical form of an object or material and making a new object from the altered material.

Recycling is not waste prevention because only waste can be recycled. One must generate waste in order to recycle the waste. Therefore, if you are recycling, you have already generate waste. Although recycling is a very good thing, ideally it would be better to not generate any waste.

Reuse is not recycling because reuse does not alter the physical form an object. Reuse is preferred to recycling because reuse consumes less energy and less resources than recycling. Of course, recycling consumes less energy and resources than making new replacement items with unrecycled or new material.

With recycling, you generally need to collect a material, transport it, clean and sort it, transform it (for example, melt it down, see secondary material, below), market that transformed material, make the transformed material into a new product, package the product, and market the product. Making a product out of recycled materials is better than using virgin materials, but waste prevention is even better because it is better to not create any waste. Unlike recycling, most forms of waste prevention require little, if any, transportation, processing and marketing. See the CalRecycle recycling page for more information.

If you send your waste away to be recycled, but you do not buy products made from postconsumer waste, then you are not completing the "cycle."

Examples of recycling:

  • At Home--Placing all your paper, cardboard, boxboard such as empty cereal boxes and empty toilet paper tubes, into the recycle bin, and then purchasing paper products made from post consumer recycled paper. Note that if you "recycle" paper, plastic, or anything, but you do not buy products made from postconsumer recycled material, then you are not completing the "cycle."
  • In Business--Old tires can be ground up and used to make a wide variety of things, including  rubber mats, door mats, pet food bowls, and playground cover. The canvas covered mats in marital arts dojos are commonly stuffed with ground up tires. Used motor oil can be reprocessed into new motor oil, and motor oil made from this "rerefined" oil is widely available.

Composting is a form of recycling.

Reuse--Using an object or material again, either for its original purpose or for a similar purpose, without significantly altering the physical form of the the object or material.

Reuse is not recycling, because recycling alters the physical form of an object or material. Reuse is generally preferred to recycling because reuse generally consumes less energy and resources than recycling. Waste is defined as material for which no use or  reuse is intended. Thus, reuse prevents objects and materials from becoming waste. Therefore, reuse is considered to be a form of waste prevention. Examples of reuse follow. To learn more about reuse, consult the CalRecycle Reuse Web site.

  • At Home--Wash and reuse your plastic food bags or consider purchasing reusable cloth bags.. Buy reusable storage containers to store leftover food, and to store foods that you buy in bulk. Consult material exchanges to purchase used items or to find new homes for items that you no longer need. If you remodel your home, consider using reused building materials, and send demolition materials that you create for reuse. Bring a reusable coffee mug or commuter mug with you when you buy coffee drinks. Many coffee shops offer discounts for customers using their own mugs.
  • In Business--Purchase "recycled" ink and toner cartridges for your printers and photocopiers.  Have the tires on your cars retreaded when the tread is worn, but the tire is otherwise reusable.

One exception to the normal preference of reuse to the purchasing new items might be some appliances. It is often environmentally preferable to replace very old refrigerators, clothes washers, clothes dryers, or central heating and air conditioning units with new appliances if given a choice between repair and replacement, because the amount of energy (and water, in the case of clothes washers) used to operate some older appliances is substantially more than the amount used to operate new appliances. Of course attempts should be made when replacing appliances to have the metal in the discarded appliances recycled.

Secondary Material--This term traditionally refers to industrial byproducts of a manufacturing process that are used as an ingredient of another manufacturing process to create another product. Traditional usage of the term, secondary material, does not refer to scrap or fragments generated by a manufacturing process and subsequently returned to the same manufacturing process. However, some recent usage of the term, secondary material, contradicts the traditional definition. In some cases the term, secondary material, does include scrap or fragments generated by a manufacturing process and subsequently returned to the same manufacturing process. There is a contradiction between how this term is defined in Section 42002 (f) of the Public Resources Code and in Section 12200 (c) of the Public Contract Code.

Sharps Waste--Go to CalRecycle's Sharps Waste web page. You may also want to visit our page on health care waste at home.

Solid Waste--In general terms, solid waste refers to garbage, refuse, sludges, and other discarded solid materials resulting from residential activities, and industrial and commercial operations. This term generally includes used oil. This term generally does not include solids or dissolved material in domestic sewage or other significant pollutants in water such as silt, dissolved or suspended solids in industrial wastewater effluents, dissolved materials in irrigation return flows or other common water pollutants. However, if any of these materials are separated from the water that carries them, then they generally are considered solid waste. For regulatory purposes, hazardous waste is a subset of solid waste.

Source Reduction--Section 40196 of the California Public Resources Code defines source reduction as any action which causes a net reduction in the generation of solid waste. "Source Reduction" includes, but is not limited to, reducing the use of nonrecyclable materials, replacing disposable materials and products with reusable materials and products, reducing packaging, reducing the amount of yard wastes generated, establishing garbage rate structures with incentives to reduce the amount of wastes that generators produce, and increasing the efficiency of the use of paper, cardboard, glass, metal, plastic, and other materials. "Source Reduction" does not include steps taken after the material becomes solid waste or actions which would impact air or water resources in lieu of land, including, but not limited to, transformation. See §40196 of the California Public Resources Code. Also see California Code of Regulations, Title 22 §67100.1 (o).

An alternative definition to the one in the statute was adopted by the CalRecycle in May 1993 (as recommended in the Statewide Waste Prevention Plan). This definition highlights the role of individuals as well as organizations, clearly states that source reduction occurs before anything enters the waste stream; and addresses the question of the overall environmental impacts.

"Any action undertaken by an individual or organization to eliminate or reduce the amount or toxicity of materials before they enter the municipal solid waste stream. This action is intended to conserve resources, promote efficiency, and reduce pollution."

The United States Environmental Protection Agency defines the term, source reduction, as follows:

"Source reduction is the design, manufacture, purchase, or use of materials or products (including packages) to reduce their amount or toxicity before they enter the municipal solid waste stream. Because it is intended to reduce pollution and conserve resources, source reduction should not increase the net amount or toxicity of wastes generated throughout the life of a product."

The above definition emphasizes the process of how waste is generated. Analyzing this process helps us find source reduction opportunities. The last sentence of the definition handles life-cycle questions that often arise when substituting products or packaging. As you can see, waste prevention, or source reduction, has everyday opportunities such as when mowing your lawn, buying pet food, and in industrial settings such as when designing consumer products.

Source Reduction is used synonymously with the term, waste prevention, defined above. The combined experience of other states and public interest groups indicates that it is easier to understand the term waste prevention. Therefore, the CalRecycle adopted the term waste prevention in May 1993. Check how the terms are being used when reviewing documents or in conversation to avoid confusion.

Sustainability--Meeting the needs of the present generation without compromising the ability of future generations to meet their own needs.  (See Our Common Future: The World Commission on Environment and Development, Bruntland, G (ed) (1987), Oxford: Oxford University Press.)

Transformation--Transformation refers to incineration, pyrolysis, distillation, or biological conversion other than composting. The statutory definition of transformation does not include composting, gasification, or biomass conversion. See §40201 of the California Public Resources Code.

Universal Waste--Sometimes called U-Waste, they are any of the wastes that are listed in section 66261.9 of division 4.5 of title 22 of the California Code of Regulations.

The term, universal waste, was coined by U.S. EPA in an attempt to describe wastes that seem to come from everywhere. The term results in part from an early federal method of identifying hazardous waste, which was distinctly different from the early California method of identifying hazardous waste. The earliest federal waste laws paid attention mostly to the processes that generated waste.  Certain processes, mostly manufacturing processes, were deemed to generate hazardous waste based on both scientific and political criteria. The earliest California regulations took a different approach. California identified substances in wastes that were considered hazardous based solely on risk to human health and the environment. California declared that if those substances were in waste, and if the presence of those substances in waste posed a risk to human health or the environment, then those wastes were considered to be hazardous regardless of which process generated them. Since the passage of the Resource Conservation and Recovery Act (RCRA) in 1976, there has been a blending of the two concepts, with federal regulations moving more closely to the pattern adopted by California. Additionally, RCRA allowed states to have more stringent standards than those required by federal law, and California's standards are more stringent. That is largely why the list of California universal wastes is longer than the federal list. Nevertheless, the term, universal waste, reflects the traditional federal concept of identifying processes. In the case of universal wastes, there are supposedly no processes that can be clearly identified as the source of generation because they come from an infinite number of sources. They seem "universal." Hence the term. California universal wastes include:

  • Batteries--Includes AAA, AA, C, D, button cell, 9-volt, both rechargeable and single use. These may contain a corrosive or reactive chemicals, as well as toxic heavy metals like cadmium. (Automotive type batteries are not universal waste. However, when they become waste, they are banned from the trash.) For more information see Batteries.
  • Fluorescent lamps and tubes--Includes fluorescent tubes, compact fluorescent lamps, metal halide lamps, sodium vapor lamps, high intensity discharge (HID) lamps, and neon bulbs.  These lamps contain Mercury.  Mercury vapor might be released to the environment when they are broken. The mercury from broken lamps in trash bins could find its way to lakes and rivers during rain storms.
  • Thermostats--There is mercury inside the sealed glass "tilt switch" of the old style thermostats (not the newer electronic kind).
  • Electronic Devices--Includes televisions and computer monitors, computers, printers, VCRs, cell phones, telephones, and radios. These devices often contain heavy metals like lead, cadmium, copper, and chromium.
  • Electrical Switches--Some electrical switches and relays contain mercury.  Such mercury switches can be found in some chest freezers, pre-1972 washing machines, sump pumps, electric space heaters, clothes irons, silent light switches, automobile hood and trunk lights, and ABS brakes.
  • Pilot Light Sensors--Mercury-containing switches associated with pilot light sensors are found in some gas appliances such as stoves, ovens, clothes dryers, water heaters, furnaces and space heaters.
  • Mercury Gauges--Some gauges, such as barometers, manometers, blood pressure, and vacuum gauges contain mercury.
  • Mercury Added Novelties--Examples include greeting cards that play music when opened; athletic shoes (made before 1997) with flashing lights in soles; and mercury maze games.
  • Mercury Thermometers--Mercury thermometers typically contain about a half gram of mercury. Many health clinics, pharmacies and doctor’s offices have thermometer exchange programs that will give you a new mercury-free fever thermometer in exchange for your old one.
  • Non-Empty Aerosol Cans that Contain Hazardous Materials--Many products in aerosol cans are toxic. And many aerosol cans contain flammables, like butane, as propellants for products like paint. If your aerosol can is labeled with words like TOXIC or FLAMMABLE don’t put it in the trash unless it is completely empty.

Waste--Objects or materials for which no use or reuse is intended.

Some statutory and regulatory definitions use the terms discarded, relinquished, stored, and accumulated to define waste.

Waste Diversion--As defined in California statute, the combined efforts of waste prevention, reuse, and recycling practices.

Waste Management Hierarchy--The order of preference of waste management techniques, reduce, reuse, recycle, dispose, as specified in §40051 and §40196 of the California Public Resources Code. This is to say that individuals and businesses should look for opportunities to reduce the waste that they generate before they practice any other option. After all attempts to reduce or eliminate the generation of waste have been exhausted, the next preferred option is to look for opportunities to reuse items or substances which could become waste. If all waste reduction and reuse options are exhausted, individuals and businesses should try to recycle waste items or substances. Note that, in general, items and substances are not considered to be waste if they are reused, and not recycled or discarded. Items or substances that are recycled are considered waste.

Waste Minimization--Refers to reducing or eliminating, and recycling, hazardous waste.

Waste Prevention--Actions or choices that prevent the generation of waste.

Common examples of waste prevention:

  • At Home--Avoiding the use of disposable utensils, napkins, and paper towels, and other disposable products. Buying durable items that will last longer than less durable items. Buying breakfast cereal, rice, or other grain-related foods in bulk, and store these items in reusable containers until needed. This eliminates the boxes used to package and store smaller portions.  Note that buying a case of individual boxes of cereal would not help prevent packaging waste, although it might help reduce the frequency of automobile trips to the store.
  • In Business--Buying cases of paper in which the paper is not packaged in individual reams.  Some paper companies provide paper this way.  Why package the package?  By not creating individual packages of 500 sheets you can just open a box of paper next to the photocopier or printer, and put what they need into the machine. There is no hassling with wrappers, and more importantly, no wrapping paper waste is created.

Waste prevention is used synonymously with the term source reduction which is defined above. The combined experience of other states and public interest groups indicates that it is easier to understand the term waste prevention. Therefore, the CalRecycle adopted the term waste prevention in May 1993. A number of local jurisdictions in California, public interest groups and a few states also use the term, waste prevention, synonymously with waste reduction, also defined below. Check how the terms are being used when reviewing documents or in conversation to avoid confusion.

U.S. EPA and many states use this term to mean any action undertaken to eliminate or reduce the amount or toxicity of materials before they enter the municipal solid waste stream. Reuse is a type of waste prevention. Waste prevention is a type of waste reduction. Waste Prevention is a type of pollution prevention.

Note: Recycling is not a form of waste prevention. See the definition of recycling for more information.

Waste Reduction--Actions taken before waste is generated to either reduce or  completely prevent the generation of waste. The combined efforts of waste prevention, reuse, composting, and recycling practices. A number of local jurisdictions in California, public interest groups and a few states use waste reduction synonymously with waste prevention, defined above. Check how the terms are being used when reviewing documents or in conversation to avoid confusion.

Worm Composting--Worms feed on slowly decomposing materials (e.g, vegetable scraps) to produce a nutrient rich soil amendment, in a controlled environment. For more information, see the CalRecycle worm pages.

Vermicomposting--Same as worm composting, above.

Xeriscaping--The practice of landscaping with slow growing, drought-tolerant plants. For more information see the CalRecycle xeriscaping page.


The forgoing definitions are provided to help those who want to improve or maximize their personal or business waste reduction efforts in order to conserve plant and mineral resources, energy, and water, and in order to reduce the pollution of water, soil, and air. The foregoing are not intended to provide legal definitions of waste or any terms related to waste. If you are looking for such definitions, please refer directly to the statutes and regulations that apply to your activities.

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Last updated: March 30, 2017
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