The sunken offshore rig currently pumping thousands of gallons of oil into the Gulf of Mexico wasn’t equipped with a shutoff mechanism that can be triggered remotely. The device, called an acoustic switch, is considered a weapon of last resort when it comes to sealing off ruptured offshore wells, but isn’t required on platforms operating under U.S. laws. By contrast, both Norway and Brazil require acoustic switches, although their effectiveness is the subject of debate. The revelation comes as U.S. federal agencies and London-based BP, who hired the Deepwater Horizon rig, are spending millions each day trying to contain the widening spill. While the Deepwater Horizon rig had a shutoff switch that would have sealed a valve on the ocean floor, it’s possible the switch was damaged or workers were unable to reach it following the explosion. Eleven people died in the accident. The rig also had a “dead man” switch that was supposed to activate in the case of a catastrophic failure on the rig.