Adam Rich’s cause of death revealed months after he died

Former child star Adam Rich died of an accidental fentanyl overdose in January at the age of 54, TMZ reported Friday.

The “Eight Is Enough” star also had non-toxic levels of alcohol and the generic version of Ativan, called lorazepam, in his system, according to an autopsy report the outlet obtained from the LA County Medical Examiner-Coroner.

The Post has contacted reps for Rich and the medical examiner for comment.

Rich was found dead in his LA home on Jan. 8. Authorites allegedly noted white powder when they arrived, suspecting he may have overdosed.

Police said no foul play was involved.

According to the autopsy report, his body was in a “state of mild decomposition.”

Rich played Nicholas Bradford — the youngest son in the Bradford clan — from 1977-1981 on “Eight Is Enough.” Other credits include “Code Red” in 1981 and “Dungeons & Dragons” in 1983.

He mostly retired from acting in the 1980s after revealing he hated being in the spotlight.

Rich long struggled with drugs. In 1991, he was arrested and accused of pocketing a drug-filled syringe at an LA hospital, where he was being treated for a dislocated shoulder.

In 2002, Rich was arrested again, for driving under the influence of what appeared to be drugs after he drove into a closed highway lane and almost hit a California Highway Patrol car.

He had been in rehab for drugs at least three times.