what careers do people with majors in environmental science usually go into?

There are not a lot of great options for an Env. Science degree. Consulting work is one of the main ones, but that work depends on the regulatory environment (companies do not typically hire env. consultants unless they need to adapt business practices to maintain environmental compliance). Similarly, a lot of env. science degree holders go into government working for a state's Dept. of Ecology or Dept. of Environment or whatever they call it locally. At the national level, the EPA hires env. scientists.

However, my hunch is that with the current make-up of the government, and it's right-ward shift with emphasis on less environmental regulation, there will be fewer and fewer jobs in the short term. That might change in a decade or so, once the environmental costs of this strategy are felt by more and more people.

I'm sorry this isn't a very rosy outlook. In my opinion you are better off, far better off, getting a pure science degree (e.g., chemistry, biology, etc.) than a derivative degree (at least at the undergraduate level). You have far more career options that way and having a B.S. in Chemistry does not prevent you from getting a job working as an environmental chemist. However, having an env. science degree is a big obstacle if the only jobs available are for "analytical chemist" and not env. science.