A remote shut-off device used in two other major oil-producing nations as a last-resort safety measure to prevent underwater oil spills is not required in the United States, the Wall Street Journal reports.

The device, known as an acoustic switch, is activated from off-site when a platform is damaged and the primary shut-off system doesn’t work. Norwegian companies have used the system on almost all its offshore drills since 1993, and it is effectively required by Norway and Brazil.

Although it’s not clear that an acoustic switch would have stopped the leak caused by last week’s oil rig explosion in the Gulf of Mexico, BP, which hired the rig, has acknowledged that the primary shut-off systems failed to work, the Journal reports.

Regulators in the United States considered requiring acoustic switches several years ago, but drilling companies were concerned about the cost, and the Minerals Management Service decided they were not necessary. A switch costs about $500,000, and BP estimates that the daily cost of dealing with the Gulf of Mexico spill is $6 million.