Later they rejected one of their chosen studies, bringing the total to 30. The CRS was highly critical of both the EPA's methods and conclusions. In other words, some of the information was unverified hearsay. The EPA used data from one uncompleted study, the Fontham study, and ignored the other two, Brownson and Kabat. Philip Morris recently won a lawsuit to gain access to it.
Most researchers routinely make their raw data available after studies have been published.
The EPA based their numbers on a meta analysis of just 11 studies. So they doubled their margin of error. Where you'd usually see 100 cases of cancer you'd see 119. A RR of less than 2.0 is usually written off as and insignificant result, most likely to be due to error or bias. An RR of 3.0 or higher is considered desirable.