Pa Yang, 57; Mai Vue Vang, 58; and True Thao, 52, were returning to the U.S. from Vientiane, Laos via Narita, Japan, U.S. Customs and Border Protection officials said.
Border patrol officers said the women arrived in Chicago carrying $3 million worth of opium in their luggage.
Piccirilli said it started routinely enough with an officer asking the women, who are all U.S. citizens, about their flight from Japan: Why they were there, and what they did?
He said their answers aroused suspicion, and that's when officers opened their bags.
"Each passenger's luggage was found to contain bags of tea leaves. Once we opened those bags we found the individual packages of a brown substance that tested positive for opium," Piccirilli said.
Piccirilli said there were 470 packets of opium concealed in those tea bags. The drugs alone weighed nearly 70 pounds.
The women appeared in court Wednesday, where a judge set bond at $50,000 for each.
While the bust was big, Customs and Border Protection officers said people try to come up with new ways to bring illegal items into the country every day.
"We see several types of concealment methods, from false-sided bags to body carries where they're wrapping narcotics around their body to make it look like they're just wearing baggy clothes," Piccirilli said.
The three women were heading to Minnesota. Prosecutors said they do not have criminal records and the DEA reports they were not on any watch lists.