Synopsis As Introduced Amends the Workers' Compensation Act. Defines "accident" and "injury." Provides that "injury" includes the aggravation of a pre-existing condition by an accident arising out of and in the course of the employment, but only for so long as the aggravation of the pre-existing condition continues to be the major contributing cause of the disability. Provides that an injury resulting directly or indirectly from idiopathic causes is not compensable. No longer allows an employee to choose in writing to decline their employer's preferred provider program. Makes changes concerning the determination of the level of permanent partial disability. Effective immediately.