Microsoft didn't immediately respond to an e-mailed request for comment. The software vendor has gained for Open XML from Ecma International, another standards group based in Geneva, and it now is seeking ISO approval as well. If that happens, both ODF and Open XML potentially could become eligible for governments to use under any of the proposed new mandates.

That could further muddy the already unclear effect that open document policies can have on government agencies. For instance, Massachusetts in late 2005 became the first state to adopt a plan to shift to open document formats. But last August, state officials that government agencies there would continue to use Microsoft Office for now while adding plug-ins that would let end users open and save files in ODF.

That move was made partly to satisfy advocates for people with disabilities, who had contended that desktop applications such as OpenOffice are less compatible than Microsoft Office is with screen readers and other accessibility tools used by blind, deaf and mobility-impaired end users. In addition, Louis Gutierrez, then the state's CIO, wrote in an e-mail to its IT advisory board that he had sought an approach that would be economical and minimally disruptive to the affected government agencies.

The California bill was proposed by state assembly member Mark Leno, a Democrat who represents the eastern part of San Francisco, including its Marina, downtown and industrial-but-gentrifying South of Market neighborhoods. Leno's Sacramento office didn't return a call seeking comment on the measure.