UNITED NATIONS, Nov 6 (Reuters) - Tests by U.S. authorities have confirmed that substances found in a U.N. office and at first feared to be a chemical weapon from Iraq were in fact harmless, the United Nations said on Tuesday. A major scare erupted after material believed to have been taken from Iraq 11 years ago by U.N. weapons inspectors was found on Aug. 24 as the inspectors were closing down their offices near the main U.N. headquarters in New York City. The United Nations said at the time it had found papers indicating the substances included phosgene, a choking chemical that attacks the lungs, used in World War One. They called in the U.S. Federal Bureau of Investigation to remove it. U.N. officials soon said preliminary tests suggested it was not phosgene after all, and U.N. spokeswoman Marie Okabe said on Tuesday that had now been confirmed. "No chemical warfare agents or related compounds were identified in the samples analyzed," Okabe told a regular news briefing. News of the discovery, first announced on Aug. 30, affected stock markets after an erroneous media report that it was nerve gas and U.N. headquarters had been evacuated. U.N. officials said the substances turned out to be organic solvents and other harmless chemicals and compounds, including camphor. Okabe said a three-member U.N. fact-finding panel set up to look into the incident had made a number of recommendations to prevent similar scares in future. Ewen Buchanan, spokesman for the U.N. Monitoring, Verification and Inspection Commission, or UNMOVIC, said at the time inspectors had to assume a worst-case scenario and take immediate precautions. "No one is going to pull the top off the bottle and sniff it," he said. The inspectors discovered the substances when they dismantled their vast archives, the end of a 16-year effort to destroy Iraq's weapons of mass destruction, many of which were rendered harmless in the 1990s. (Reporting by Patrick Worsnip; Editing by John O'Callaghan)