The D.C. Council will vote tomorrow on a proposal to ban transportation of hazardous chemicals through D.C. on rail cars. If the issue sounds familiar, it’s because the Council considered and then rejected partly due to skepticism from the mayor’s office.

This time around the proposal seems to be a sure thing: nine members and the mayor have said they support the law. Although the council members have cited terrorism threats, a rail crash in January in South Carolina that killed nine and injured hundreds may have helped persuade doubters.

The AFL-CIO Washington Council has issued an alert to their members urging them to write to the D.C. Council in support of the bill, calling the current voluntary agreement between the Department of Homeland Security and the freight carrier CSX “inadequate and unenforceable.”