This warning light only comes on when the airbag(safety restraint system) module detects a fault in the SRS. This can range from a bad seat belt tensioner, fauty airbag, short/open in wiring harness, faulty crash sensor, or faulty SRS control module. The only way to know why is to have the SRS module with a diagnostic scanner with SRS capability for SRS fault codes and then repair. Once repair is made then the light will go off. There is no other way to reset the light- disconnecting the battery wont do it, as will nothing else. As long as this light is on, the SRS system, including airbags will not deploy in the event of an accident
If the module itself if bad, then it has to be replaced. This would run about $800 for the part. But before assuming its the module, have it read for stored fault codes as it could be a seat belt tensioner, an airbag, the coil behind the airbag, a crash sensor, or an short or open in the wiring harness.