from PBS.
Gavin Schmidt, a climatologist at NASA’s Goddard Institute for Space Studies, is interviewed on a PBS program regarding the difference between skepticism and denial from a scientific point of view in the context of climate change. In the interview he refers to a group of scientists and non-scientists who have been deliberately spreading disinformation about acid rain, ozone depletion, air pollution, etc., but this government sponsored program interviewer carefully steers away from exploring the details of this serious charge.
For a detailed explanation of this disinformation campaign that Schmidt referred to, you simply must read Merchants of Doubt by Oreskes & Conway.