Waste Management, Inc., through its subsidiaries, engages in the provision of environmental solutions to residential, commercial, industrial, and municipal customers in the United States and Canada. It offers collection services, including picking up and transporting waste and recyclable materials from where it was generated to a transfer station, material recovery facility (MRF), or disposal site; and owns and operates transfer stations, as well as owns, develops, and operates landfill facilities that produce landfill gas used as renewable natural gas for generating electricity. As of December 31, 2022, the company owned or operated 254 solid waste landfills, five secure hazardous waste landfills, 97 MRFs, and 337 transfer stations. It also provides materials processing and commodities recycling services at its MRFs, where cardboard, paper, glass, metals, plastics, construction and demolition materials, and other recycling commodities are recovered for resale or redirected for other purposes; recycling brokerage services, such as managing the marketing of recyclable materials for third parties; and other strategic business solutions. In addition, the company offers construction and remediation services; services related with the disposal of fly ash, and residue generated from the combustion of coal and other fuel stocks; in-plant services comprising full-service waste management solutions and consulting services; and specialized disposal services for oil and gas exploration and production operations. The company was formerly known as USA Waste Services, Inc. and changed its name to Waste Management, Inc. in 1998. Waste Management, Inc. was incorporated in 1987 and is headquartered in Houston, Texas.

Republic Services, Inc., together with its subsidiaries, offers environmental services in the United States and Canada. It is involved in the collection and processing of recyclable, solid waste, and industrial waste materials; transportation and disposal of non-hazardous and hazardous waste streams; and other environmental solutions. Its residential collection services include curbside collection of material for transport to transfer stations, landfills, recycling centers, and organics processing facilities; supply of recycling and waste containers; and renting of compactors. The company also engages in the processing and sale of old corrugated containers, old newsprint, aluminum, glass, and other materials; and provision of landfill services. It serves small-container, large-container, and residential customers. The company was incorporated in 1996 and is based in Phoenix, Arizona.

Clean Harbors, Inc. provides environmental and industrial services in the United States and internationally. The company operates through two segments, Environmental Services and Safety-Kleen Sustainability Solutions. The Environmental Services segment collects, transports, treats, and disposes hazardous and non-hazardous waste, such as resource recovery, physical treatment, fuel blending, incineration, landfill disposal, wastewater treatment, lab chemicals disposal, and explosives management services; and offers CleanPack services, including collection, identification, categorization, specialized packaging, transportation, and disposal of laboratory chemicals and household hazardous waste. This segment also provides industrial maintenance and specialty industrial services; and utilizes specialty equipment and resources that performs field services. The Safety-Kleen Sustainability Solutions segment provides pickup and transportation services for hazardous and non-hazardous containerized waste for recycling or disposal; machine cleaning and maintenance, and disposal and replenishment of clean solvent or aqueous fluids; and vacuum services to remove solids, residual oily water, and sludge and other fluids from customers' oil/water separators, sumps, and collection tanks, as well as removes and collects waste fluids found at large and small industrial locations, including metal fabricators, auto maintenance providers, and general manufacturers. This segment also manufactures, formulates, packages, distributes, and markets lubricants and other automotive products. Clean Harbors, Inc. was incorporated in 1980 and is headquartered in Norwell, Massachusetts.

Enpro Inc. design, develops, manufactures, and markets proprietary, value-added products and solutions to safeguard critical environments in the United States, Europe, and internationally. It operates through two segments, Sealing Technologies and Advanced Surface Technologies. The Sealing Technologies segment offers single-use hygienic seals, tubing, components and assemblies; metallic, non-metallic, and composite material gaskets; dynamic seals; compression packing; hydraulic components; expansion joints; and wall penetration products for chemical and petrochemical processing, pulp and paper processing, nuclear energy, hydrogen, natural gas, food and biopharmaceutical processing, primary metal manufacturing, mining, water and waste treatment, commercial vehicle, aerospace, medical, filtration, and semiconductor fabrication industries. The Advanced Surface Technologies segment offers cleaning, coating, testing, refurbishment, and verification services for critical components and assemblies used in semiconductor manufacturing equipment, as well as for critical applications in the space, aerospace, and defense markets; and specialized optical filters and thin-film coatings for various applications in the industrial technology, life sciences, and semiconductor markets. The company was formerly known as EnPro Industries, Inc. and changed its name to Enpro Inc. in December 2023. Enpro Inc. was incorporated in 2002 and is headquartered in Charlotte, North Carolina.

Quaker Chemical Corporation, doing business as Quaker Houghton, provides industrial process fluids for steel, aluminum, automotive, aerospace, offshore, can, mining, and metalworking companies worldwide. The company, together with its subsidiaries, develops, produces, and markets various formulated specialty chemical products and offers chemical management services for various heavy industrial and manufacturing applications. It offers metal removal fluids, cleaning fluids, corrosion inhibitors, metal drawing and forming fluids, die cast mold releases, heat treatment and quenchants, metal forging fluids, hydraulic fluids, specialty greases, offshore sub-sea energy control fluids, rolling lubricants, rod and wire drawing fluids, and surface treatment chemicals. The company was founded in 1918 and is headquartered in Conshohocken, Pennsylvania.

CECO Environmental Corp. provides critical solutions in industrial air quality, industrial water treatment, and energy transition solutions worldwide. It operates in two segments: Engineered Systems and Industrial Process Solutions. The company engineers, designs, manufactures, and installs non-metallic expansion joints and flow control products, including rubber expansion joints, ducting expansion joints, and industrial pinch and duck bill valves; membrane-based industrial water and wastewater treatment systems; and provides dust and fume extraction solutions comprising consultation, design, manufacturing, installation, and service, as well as water and wastewater treatment solutions. It offers engineered and configured products and solutions, including dampers and diverters, expansion joints, selective catalytic reduction systems, severe-service and industrial cyclones, dust collectors, thermal oxidizers, filtration systems, wet and dry scrubbers, separators and coalescers, water treatment packages, metallic and non-metallic pumps, industrial silencers, and fluid handling equipment, as well as plant engineering services and engineered design build fabrication services. In addition, the company offers industrial engineered noise control solutions, including custom acoustical gen-set packages, ambient air baffles, acoustical louvres, and skid enclosures; process filtration solutions for hydrocarbon and chemical processing; and energy and water conservation systems and equipment. The company markets its products and services to natural gas processors, transmission and distribution companies, refineries, power generators, industrial manufacturing, engineering and construction companies, semiconductor manufacturers, compressor manufacturers, beverage can manufacturers, metals and minerals, and electric vehicle producers. CECO Environmental Corp. was founded in 1869 and is headquartered in Dallas, Texas.

Ecovyst Inc. offers specialty catalysts and services in the United States and internationally. The company operates in two segments, Ecoservices and Advanced Materials & Catalysts. The Ecoservices segment provides sulfuric acid recycling services and end-to-end logistics for production of alkylate for refineries; and virgin sulfuric acid for mining, water treatment, and industrial applications. The Advanced Materials & Catalysts segment offers advanced materials and specialty catalyst products and process solutions to producers and licensors of polyethylene and advanced silicas. This segment also supplies specialty zeolites and zeolite-based catalysts to customers for refining of oil primarily hydrocracking catalyst and dewaxing, sustainable fuels, and emission control systems for both on-road and non-road diesel engines. The company was formerly known as PQ Group Holdings Inc. and changed its name to Ecovyst Inc. in August 2021. Ecovyst Inc. was founded in 1831 and is headquartered in Malvern, Pennsylvania.

Envela Corporation, together with its subsidiaries, operates in the re-commerce sector in the United States. The company operates through two segments, Commercial-Services and Direct-To-Consumer. It provides end-of-life asset recycling; data destruction and IT asset management; and products, services, and solutions to industrial and commercial companies, as well as operates as a re-commerce retailers of luxury hard assets. The company buys to resell or recycle luxury hard assets, including jewelry, diamonds, gemstones, fine watches, rare coins and related collectibles, precious-metal bullion products, gold, silver and other precious metals; buys and sells various forms of gold, silver, platinum, and palladium products, including United States and other government coins, and private mint medallions, as well as numismatic items, such as rare coins, currency, medals, tokens, and other collectibles; and provides jewelry and watches repair services, as well as custom jewelry services. In addition, it offers end-of-life electronics recycling services; disposal transportation and product tracking services; IT equipment disposition services, including compliance and data sanitization services; services to companies in the areas of upgrade capabilities and dispose of equipment; and asset- disposition solutions to government agencies, middle-market firms, major corporations, and other organizations. The company operates multiple brick-and-mortar and online marketplaces; and offers custom re-commerce solutions to meet the needs of various clients. It operates through DGSE.com, echoenvironmental.com, ITADUSA.com, teladvance.com and AvailRecovery.com. websites. The company was formerly known as DGSE Companies, Inc. and changed its name to Envela Corporation in December 2019. Envela Corporation was incorporated in 1965 and is headquartered in Irving, Texas.