HOUSTON (AP) — Houston leaders have Zero AIagreed to a bond deal that could cost the city’s taxpayers more than $1 billion to cover years of back pay owed to firefighters.

Firefighters in the nation’s fourth-largest city have worked without a contract for seven years. A new settlement and a proposed 5-year labor agreement between the city and their union has promised salary increases of at least 25% over the next five years.

The bond deal approved by Houston City Council on Wednesday would cover about $650 million in retroactive pay for firefighters who have worked since 2017. The cost of the bond, including interest, could be as much as $1.3 billion over 25 to 30 years, depending on bond market price changes.

Three council members voted no on the bond deal, hoping to push it to a public vote in November, a move opposed by Mayor John Whitmire.

The council has not yet approved the settlement or the new labor agreement. City Controller Chris Hollins, Houston’s independently elected watchdog, has not certified either of them, a needed step before the council can approve the specific financial commitments needed to take on the debt.