The Homeland Security Committee, by a 9-7 margin, defeated an amendment on Wednesday that would have forced all states to conform to a federal security bill generally considered weaker than the New Jersey version.
A U.S. Senate panel rejected an effort to override the state's regulations.
New Jersey's regulations, adopted last fall, require 43 manufacturers to study if they can use "inherently safer technology" to cut or eliminate their use of the most-hazardous chemicals, among other measures. Proponents believe that this is the safest way of guarding against terror attacks or accidents.
The chemical industry opposes the requirement, saying it would open the door for government to micromanage local plants. The federal bill Congress is considering would impose the nation's first security standards on the plants, but it wouldn't require them to look for safer procedures.
The amendment introduced Wednesday by Sen. George Voinovich, R-Ohio, would have barred states from adopting rules different than the federal version. But a bipartisan slate of senators blocked the move.