Several OPCW officials and delegates to this week's special session at OPCW headquarters here agreed that Bustani had displayed a secretive and abrasive management style, offending a number of key governments in the organization.
The United States was also angered by Bustani's attempts to persuade Iraq to join the OPCW, which Washington argued would undermine the UN Security Council resolutions demanding that Iraq submit to inspection by the UN Monitoring, Verification and Inspection Commission, (UNMOVIC) of any nuclear, biological and chemical weapons facilities it might still possess.
Critics of US policy have suggested that hardliners in Washington feared Iraq's membership in the OPCW, which would subject it to the organization's own chemical weapons inspections, might undercut their plans to topple Saddam Hussein on the grounds that he was keeping international weapons inspectors out.
President Hussein has refused to allow UNMOVIC weapons inspectors into Iraq since they were withdrawn in 1998.
The senior US official dismissed such arguments as "an atrocious red herring," saying Washington would welcome Iraq's membership of the OPCW so long as it also accepted UNMOVIC inspections.
But the US campaign against Bustani, which turned into an ugly row involving allegations of slander and the publication of private diplomatic correspondence, has raised fears in some quarters about the future of the multilateral system in the face of US determination to pursue its own interests.
Bustani's dismissal marks the second time in less than a week that Washington has won the removal of a senior UN official with whom it disagreed. Last Friday, after intense US lobbying, a US scientist who favors vigorous action to slow global warming lost his job as head of the Intergovernmental Panel on Climate Change.