Currently, the states with reported E. coli cases are Alaska, Arizona, California, Connecticut, Idaho, Illinois, Louisiana, Michigan, Missouri, Montana, New Jersey, New York, Ohio, Pennsylvania, Virginia, and Washington.
If you're dead-set on purchasing chopped romaine, the CDC has further advice: "Before purchasing romaine lettuce at a grocery store or eating it at a restaurant, confirm with the store or restaurant that it is not chopped romaine lettuce from the Yuma, Arizona growing region. If you cannot confirm the source of the romaine lettuce, do not buy it or eat it."
Not that you need a reminder, but getting infected with E. coli totally sucks. This particular outbreak concerns Shiga toxin-producing bacteria, which the CDC says causes diarrhea, vomiting, and cramps among other symptoms. It usually takes about one week to recover, although in some cases hospitalization is required.