Clean Harbors Inc (CLH)

How it makes money

Most revenue is fee-for-service: customers pay per tonne, per drum, per hour or per job to have waste taken away and destroyed, or to have a plant cleaned, a turnaround supported or a spill contained. Waste that reaches Clean Harbors' own incinerators and landfills is billed at a disposal price the company sets, which is why internalising volume matters to it. A recurring, route-based layer comes from small-quantity generators — garages, workshops and small factories served on a scheduled branch route with containerised waste pick-up, parts-washer and vacuum services. In Safety-Kleen Sustainability Solutions the economics invert: the company earns, or pays, on the spread between what it charges to collect used oil and what it can sell re-refined base oil and blended lubricants for, so results move with base oil prices. In 2025 the company pushed a 'charge-for-oil' pricing model to widen that spread.

Revenue by segment

The advantage sits in permits, not in technology. Hazardous-waste incinerators and landfills need permits that take years of regulatory and local approval and are effectively not being granted for new North American greenfield capacity, so the ten incinerators and seven landfills Clean Harbors already operates cannot be replicated by a competitor with capital alone. That network also lets the company internalise waste collected by its own routes, capturing both the service and the disposal price. The re-refining business has no comparable protection: it sells a commodity output at market prices.

A large share of the work is non-discretionary: waste that a factory or refinery produces must be legally disposed of whether or not the economy is strong, and that gives the base business a defensive floor. On top of that floor sit clearly cyclical layers — plant turnarounds, large remediation and construction projects, landfill volumes tied to project activity, and industrial production levels in chemicals, refining and automotive, the three heaviest customer industries. The re-refining segment is the most exposed, since it rides the base oil price cycle; in 2025 weaker base oil pricing pushed its revenue down while the environmental side grew. Emergency response adds an unpredictable, event-driven swing in both directions. Management points to reshoring, PFAS rules and a growing remediation pipeline as multi-year demand drivers.

Key risks

• Environmental liabilities from its own sites — The company discloses remediation and post-closure liabilities of $241.5 million tied to its waste facilities, and says handling hazardous materials exposes it to closure, remediation and clean-up costs that can exceed what is reserved.
• Regulation, permits and climate legislation — Clean Harbors lists rising statutory and environmental requirements, climate-change legislation and ESG rules among its risk factors: they can raise operating costs and limit its ability to obtain or renew the permits it needs to expand facilities.
• Oil price volatility — Swings in oil and base oil prices affect both the cost of collecting used oil and the price at which re-refined products can be sold, and are named by the company as a risk to the Safety-Kleen Sustainability Solutions business.
• Dependence on unpredictable emergency work — Part of the business depends on industrial accidents, spills and natural disasters, and on the regulatory decisions that follow them. These events cannot be scheduled and their absence in a given year reduces revenue.
• Landfill capacity assumptions — Accounting and cash-flow planning assume permitted landfill expansions will be granted. If those expansions are denied or delayed, the company says operations and cash flows would be affected.
• Debt load and covenants — The company carries senior notes and term loans in the billions and discloses that its leverage, and the restrictive covenants attached to it, limit financial flexibility and could trigger default if breached.
• Cybersecurity and technology failure — A breach or failure of the systems that run dispatch, routing and customer data could disrupt operations and harm customers, and the company notes its insurance may not fully cover such an event.

The filing does not disclose a top-customer percentage. It describes the customer base as ranging from small businesses to Fortune 500 companies, public, private and governmental, across many industries, and says this diversity limits credit exposure to any single customer. The concentration the company does quantify is by industry: the top ten industries served were about 80% of 2025 revenues, the largest being general manufacturing and chemical at roughly 14% each, refineries about 12% and automotive about 10%.