The President has instructed the Office of Personnel Management to develop policies to protect mothers who are breastfeeding their infants, and need time and space to pump during the day. Although the new health care law protects many hourly workers, see discussion here, the President wants all federal workers to get the protection.
While finding space may not always be easy for an employer, hence the limitation to larger employers, many employers may be pleased to find that productivity is not necessarily affected. During my own bouts of working and pumping, I found that I could at least read during these breaks. Many employees may have similar ways to use the time in some productive way with the use of audio podcasts, for example.
The policies are supposed to be announced as soon as they are ready. Since some federal agencies already have them in place, that theoretically should not take long.