The union represents building engineers, cleaners, bus aides, mechanics, and other workers who make an average of about $35,000 a year. A third of the union's members make less than $20,000.
All 2,700 have received pink slips, and the first layoffs would take effect July 15, with the rest of the workers potentially laid off by the end of the year.
Leaders of 32BJ fear the district will outsource their jobs.
Teetering on the edge of insolvency, the district is already borrowing $218 million to make ends meet for the 2012-13 school year. But it has also budgeted for $94 million in extra city money - and Council approved a budget Thursday night that will provide only $40 million.
District and city leaders are pushing in Harrisburg on two last-minute bills that would protect the district from a ruling by the state Tax Equalization Board that could cost the district tens of millions in assessment appeals by property owners.
With their backs to the wall, dozens of 32BJ members packed Council chambers Thursday, loudly demanding that Council fund schools fully, but also to require any money to be tied to a guarantee that they will keep their jobs.
Building engineer Ernie Bennett "can't sleep at night" worrying about his job. He implored Council to help send a message to the SRC.
"We need you all," Bennett said in testimony before Council. "We fought the good fight, and now we need some help. I'm humble enough to say that to you, City Council."
Bus aide Dietha Brown said she was fed up with politics and not sure what her plan B was if the layoffs go through.
"This job got me off welfare," said Brown, 61, who works as a one-on-one aide to a disabled student. The job also helped her buy a house and support her grandchild. "If I lost my job, I would lose my house. How am I going to eat? Don't put me back on the system."
Contact Kristen Graham at 215-854-5146, firstname.lastname@example.org, or follow on Twitter @newskag. Read her blog, "Philly School Files," at www.philly.com/schoolfiles.
Inquirer staff writer Troy Graham contributed to this article.