"We had 300 letters sent out last Friday, and we found out something went wrong this Monday when people started receiving the letters," Mr. Welch said. "It was mailing that just went wrong when it went through the mail service. We had Tylenol pills actually attached to the letters, but the pills got crushed in the mail-service process," he said.

One company in Shreveport, La., which received the marketing letter this week, ended up calling 911. Investigators and hazardous-materials experts arrived at the scene, but they soon determined that the suspicious powder was not a toxic substance. "We were notified by someone who received the letter?plus there were a fire chief and investigators there at the time as well," Mr. Welch said.

He emphasized, though, that nobody was upset, "because they know it was an innocent mistake." The pills were just an eye-catcher, he explained: "It was a way for us to say, ?here's how to solve one of your biggest headaches in regard to your insurance.'"

He said he doesn't think there is going to be any legal or regulatory consequences directed at this marketing mishap: "At least that's what I am hoping for. Hopefully this is over with."