The problem: The lettuce was sold under several different brand names, and the Food and Drug Administration doesn't have a complete list and isn't sure if other states received shipments, said FDA acting commissioner Lester Crawford.
The FDA urged all consumers to throw away 5-pound bags of "Romaine Toss" sold by Spokane Produce, and to ask grocery store produce managers if smaller packages of romaine came from that company.
The unusual consumer warning followed an episode at a Washington cheerleading camp in which 29 people became sick with E. coli, including a teenager whose kidneys were so damaged that she is on dialysis, the FDA said.
Doctors are investigating another 16 people who didn't attend the camp but also are suspected of having E. coli linked to the lettuce, Crawford said.
A week ago, 19 million pounds of ConAgra hamburger were recalled because of E. coli contamination blamed for sickening at least 20 people, mostly in Colorado.
E. coli is a bacterium often found in the intestinal tracts and feces of livestock. In people, it can cause bloody diarrhea, abdominal cramps and sometimes death. Most at risk are the very young, the elderly and people with weak immune systems.
Most illnesses caused by E. coli stem from eating undercooked ground beef, but manure or feces-contaminated irrigation water sometimes taints fresh produce, too.
FDA's Crawford said the Spokane Produce romaine clearly is linked to the cheerleading camp outbreak. But he said no formal recall has been issued because of problems identifying how and where the lettuce was sold, and the last known illness occurred on July 19, which suggests most of the suspect lettuce may no longer be on store shelves. Lettuce has a two-week shelf life.
Still, the FDA issued Monday's warning as a precaution in case the lettuce remains in consumers' refrigerators.
A woman answering the phone Monday at Spokane Produce refused comment.