WASHINGTON - The Canadian embassy in Washington was evacuated briefly on Thursday because of a suspicious letter, forcing out employees for more than an hour, officials said.US Secret Service and local emergency responders investigated the incident but found nothing dangerous."It was found to be non-hazardous," Secret Service spokesman Max Milien said of the letter.Embassy spokesman Chris Plunkett said the embassy's 325 employees were evacuated at around 9:30 a.m. EDT (1330 GMT) after a suspicious letter was found in the mail room.Workers spilled onto Pennsylvania Avenue, a major artery that leads to the White House just 1.5 miles (2.4 km) away, which was partially blocked off before the all-clear was given.Plunkett said embassy staff were allowed back in at around 10:35 a.m. (1435 GMT).Officials gave no other details about the contents of the letter or who sent it.