Warehouse and shipping workers at Google Express Services voted Friday to join the Teamsters union, Teamsters Local 853 in San Leandro, Calif., announced. The 151 workers at Google Express in Palo Alto, Calif., are employed through Adecco, the world’s largest staffing firm.

Workers’ concerns at the same-day delivery service include lack of ventilation in their workplace, low wages and poor benefits, as well as a requirement that workers sign employment agreements with Adecco that limit their tenure to two years, according to the Teamsters.

“We believe that our associates are better off directly dealing with us as their employer rather than involving a union, however, we are supportive of any direction freely chosen by our associates,” Adecco said in a statement provided to Staffing Industry Analysts. “Over the coming days, we’ll be reviewing the results to determine that all steps and processes were followed to ensure the election campaign was held in a lawful manner.”

Re/code reports Google Express is shutting down its two delivery hubs in San Francisco and Mountain View, Calif. The service iteself is not shutting down, according to re/code, but seems to be recalibrating a logistical plan it was testing in California.