Fame
When collaborating with many other labs across the country, the EPA typically plays a long, nine-inning game. Its research goals aren't going to be solved overnight and often take years of work before conclusions can be drawn and those findings are passed along to policy makers.
Sometimes, smaller bits of the larger research goals will get scientists national recognition, or at least recognized in their inner circle of mad scientists. And while the fame and glory of research isn't the most important aspect to the work, it's nice to have a little recognition every now and then.