Exhibit 16 [Logo of PricewaterhouseCoopers] PricewaterouseCoopers LLP 600 Grant Street Pittsburgh PA 15219 Telephone (412) 355-6000 Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 April 14, 2000 Commissioners: We have read the statements made by Calgon Carbon Corporation (copy attached), which we understand will be filed with the Commission, pursuant to Item 4 of Form 8-K, as part of the Company's Form 8-K report dated April 7, 2000. We agree with the statements concerning our Firm in such Form 8-K. Very truly yours, /s/ PricewaterhouseCoopers LLP - ------------------------------- PricewaterhouseCoopers LLP