Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2019 OR ☐ TRANSITION REPORT PURSUANT TO Section 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . Commission file number: 001-39120 US ECOLOGY, INC. (Exact name of registrant as specified in its charter) Delaware 84-2421185 (State or other jurisdiction of (I.R.S. Employer incorporation or organization) Identification No.) 101 S. Capitol Blvd., Suite 1000 Boise, Idaho 83702 (Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code: (208) 331-8400 Securities registered pursuant to Section 12(b) of the Act: Title of each class Trading Symbol(s) Name of each exchange on which registered Common Stock, par value $0.01 per share ECOL Nasdaq Global Select Market Warrants to Purchase Common Stock ECOLW Nasdaq Capital Market Securities registered pursuant to Section 12(g) of the Act: None Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ⌧ No ◻ Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ◻ No ⌧ Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ⌧ No ◻ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ⌧ No ◻ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. Large Accelerated Filer ⌧ Accelerated Filer ◻ Non-Accelerated Filer ◻ Smaller Reporting Company ☐ Emerging Growth Company ☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No ⌧ The aggregate market value of the registrant’s voting stock held by non-affiliates on June 30, 2019 was approximately $1.30 billion based on the closing price of $59.54 per share as reported on the Nasdaq Global Select Market System. At February 26, 2020, there were 31,516,432 shares of the registrant’s Common Stock outstanding. Documents Incorporated by Reference Listed hereunder are the documents, any portions of which are incorporated by reference and the Parts of this Form 10-K into which such portions are incorporated: 1. The registrant’s definitive proxy statement for use in connection with the Annual Meeting of Stockholders to be held on or about June 3, 2020 to be filed within 120 days after the registrant’s fiscal year ended December 31, 2019, portions of which are incorporated by reference into Part III of this Form 10-K. Table of Contents US ECOLOGY, INC. FORM 10-K TABLE OF CONTENTS Item Page PART I Cautionary Statement 3 1. Business 4 1A. Risk Factors 21 1B. Unresolved Staff Comments 39 2. Properties 40 3. Legal Proceedings 42 4. Mine Safety Disclosures 44 PART II 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities 44 6. Selected Financial Data 47 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations 47 7A. Quantitative and Qualitative Disclosures About Market Risk 75 8. Financial Statements and Supplementary Data 77 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure 130 9A. Controls and Procedures 130 9B. Other Information 131 PART III 10. Directors, Executive Officers and Corporate Governance 132 11. Executive Compensation 132 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters 132 13. Certain Relationships and Related Transactions, and Director Independence 133 14. Principal Accounting Fees and Services 133 PART IV 15. Exhibits, Financial Statement Schedules 133 16. Form 10-K Summary 133 SIGNATURES 137 2 Table of Contents PART I Cautionary Statement for Purposes of Safe Harbor Provisions of the Private Securities Litigation Reform Act of 1995 This annual report on Form 10-K contains forward-looking statements within the meaning of the federal securities laws. Statements that are not historical facts, including statements about the Company’s beliefs and expectations, are forward-looking statements. Forward-looking statements include statements preceded by, followed by or that include the words “may,” “could,” “would,” “should,” “believe,” “expect,” “anticipate,” “plan,” “estimate,” “target,” “project,” “intend” and similar expressions. These statements include, among others, statements regarding our financial and operating results, strategic objectives and means to achieve those objectives, the amount and timing of capital expenditures, repurchases of its stock under approved stock repurchase plans, the amount and timing of interest expense, the likelihood of our success in expanding our business, financing plans, budgets, working capital needs and sources of liquidity. Forward looking statements are only predictions and are not guarantees of performance. These statements are based on management’s beliefs and assumptions, which in turn are based on currently available information. Important assumptions include, among others, those regarding demand for the Company’s services, expansion of service offerings geographically or through new or expanded service lines, the timing and cost of planned capital expenditures, competitive conditions and general economic conditions. These assumptions could prove inaccurate. Forward looking statements also involve known and unknown risks and uncertainties, which could cause actual results to differ materially from those contained in any forward looking statement. Many of these factors are beyond our ability to control or predict. Such factors may include the integration of the operations of NRC Group Holdings Corp. (“NRC”), the loss or failure to renew significant contracts, competition in our markets, adverse economic conditions, our compliance with applicable laws and regulations, potential liability in connection with providing oil spill response services and waste disposal services, the effect of existing or future laws and regulations related to greenhouse gases and climate change, the effect of our failure to comply with U.S. or foreign anti-bribery laws, the effect of compliance with laws and regulations, an accident at one of our facilities, incidents arising out of the handling of dangerous substances, our failure to maintain an acceptable safety record, our ability to perform under required contracts, limitations on our available cash flow as a result of our indebtedness, liabilities arising from our participation in multi-employer pension plans, the effect of changes in the method of determining the London Interbank Offered Rate (“LIBOR”) or the replacement thereto, risks associated with our international operations, the impact of changes to U.S. tariff and import and export regulations, fluctuations in commodity markets related to our business, a change in NRC’s classification as an Oil Spill Removal Organization, cyber security threats, unanticipated changes in tax rules and regulations, the loss of key personnel, a deterioration in our labor relations or labor disputes, our reliance on third-party contractors to provide emergency response services, our access to insurance, surety bonds and other financial assurances, our litigation risk not covered by insurance, the replacement of non-recurring event projects, our ability to permit and contract for timely construction of new or expanded disposal space, renewals of our operating permits or lease agreements with regulatory bodies, our access to cost-effective transportation services, lawsuits, our implementation of new technologies, fluctuations in foreign currency markets and foreign affairs, our integration of acquired businesses, our ability to pay dividends or repurchase stock, anti-takeover regulations, stock market volatility, the failure of the warrants to be in the money or their expiration worthless and risks related to our compliance with maritime regulations (including the Jones Act). Except as required by applicable law, including the securities laws of the United States and the rules and regulations of the Securities and Exchange Commission (the “SEC”), we are under no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. You should not place undue reliance on our forward-looking statements. Although we believe that the expectations reflected in forward-looking statements are reasonable, we cannot guarantee future results or performance. Before you invest in our common stock, you should be aware that the occurrence of the events described in the “Risk Factors”