Postdocs at the University of California, one of the most influential US university systems, are embroiled in a debate over whether they should unionize. Some back the action, saying it would give them much-needed leverage for improving their working conditions. But others are concerned about the way in which the union in question — United Auto Workers (UAW) — has recruited people to the cause.

If formed, the group would be only the second postdoc union in the country, and by far the largest. The University of Connecticut Health Center in Farmington has had one since 2004, and it currently represents 125 postdocs. At the University of California, the UAW would act for some 5,800 postdocs.

UAW representatives, including graduate students and postdocs at the university, have gone from lab to lab collecting signatures in support of unionizing. The organization filed a petition to represent postdocs on 13 July. This month, some postdocs began a letter-writing campaign withdrawing their support, saying that they hadn't understood what was involved when they signed up.

The petition is waiting for the California Public Employment Relations Board to verify that all the signatures are valid. If the UAW has signatures from more than half of the eligible members, the union will automatically be adopted. If 30–50% of postdocs have signed, a system-wide election will be held. If less than 30% have signed, no action will be taken.

UAW representative Maureen Boyd says the union had a “strong majority” when it filed the petition. At present, it isn't clear whether postdocs can withdraw their support.

“A lot of people didn't feel they got all the information they needed,” says Gregory Potter, chair of the Postdoctoral Scholars Association of the University of California, San Francisco. He says that the UAW resisted invitations to public discussions on the topic.

A decision on the union is likely to be reached in the next few weeks.