The Service Employees International Union, which represents nursing home and healthcare employees throughout the country, will merge 240,000 California members into one “mega-local.”

SEIU officials have said the merger will give California workers a stronger voice in their state’s capital. The nearly quarter-million member local will be the second largest single group within the SEIU, according to The Los Angeles Times. Long-term care workers and home health aides from Local 521 in San Jose and United Healthcare Workers West (UHW) of Oakland will join Los Angeles’ Local 6434 to create the new group, the Times reports.

Officials at UHW of Oakland have expressed dismay over the merger, claiming that it will be forced to surrender roughly 65,000 members to the new local. The UHW has fought the merger since the SEIU first proposed it in December, and many of its members have suggested disaffiliating themselves with the SEIU. For its part, the SEIU has accused UHW of Oakland officials of misrepresenting the proposal and engaging in “scare tactics” designed to hinder the merger, reports the LA Times.