The trouble began when a North Carolina businessman e-mailed the department to ask a daily antiterrorism bulletin be sent to a different e-mail address, The New York Times reported Thursday. However, a flaw with the "reply" function of the e-mail caused more than 2.2 million messages to be sent to addresses nationwide.
Russ Knocke, a Homeland Security spokesman, said the problem was in the e-mail setup for the bulletin, the Daily Open Source Infrastructure Report.
"Human error," he said. "Very frustrating."
Knocke said the problem is expected to be fixed Thursday.
The accidental mass mailings resulted in lighthearted cross-country exchanges discussing astrological signs, wine preferences and other random topics.
"It's good here in D.C.," Bill Miller wrote from the Office of Emergency Programs in the Treasury Department. "Just a bit muggy!"