Similar to a state law that went into effect Sunday in New York, the proposal for New Jersey would offer limited legal protection to those who summon help for overdose victims, though they too may have been using illegal drugs.
No legislator has yet signed on to sponsor the measure, but some in law enforcement take a positive view.
"In general, it's something we would support," says Jason Laughlin, spokesman for the Camden County Prosecutor's Office. "It would be a rare day we would file charges in those cases."
More than 750 Garden State residents, including nearly 100 in Camden County, died of overdoses in 2009, and most were not alone when they took the drugs, according to the alliance.
DiRenzo believes Sal was not alone either, and sees the 911 measure as a lifesaver.
"When people hear 'drug addict,' they have an image," she says. "Addiction is a disease. My son had a disease. I really believe that."
An administrative assistant at a law firm, DiRenzo, 52, was born and raised in Camden. Blake Marchese, 30, teaches elementary school in Audubon, where she and Sal grew up.
The quiet and compassionate young man they knew quickly turned into a scamming drug addict after a friend offered him heroin about six years ago.
The guy who would "give you the shirt off his back," in Blake Marchese's words, ended up stealing from his mother.
"I slept with my wallet," says DiRenzo, who took her only son to detox, fought to get him into rehab, and took him to 12-step meetings. She even waited outside in the car while he went to a downtown Camden methadone clinic.
"What do you do when you can't help your child?" DiRenzo asks.
In 2007, Sal began taking Suboxone, a prescription medication that helps some people kick heroin.
He graduated from a technical school and got a job in commercial heating and air-conditioning, which he loved. His longtime girlfriend, Rianna DeLuca, gave birth to their son.
"He was Sal again," DiRenzo says.
But last year, he went back to heroin. Relapse is common with all types of addictions: Consider how often people quit smoking only to start again.
"I remember him saying to me, 'I can't help this. . . . It's not what I want to be,' " Blake Marchese says.
In June 2010, Sal got into an inpatient rehab program in Monmouth County. He was discharged to an outpatient program after two weeks and passed a drug test six days before he walked out the door in Blackwood, never to return.
On what was supposed to have been Sal's 90th day of sobriety, his body was found in that parking lot in Camden.
"People who have lost a child have told me they never get over it," says Msgr. Mike Mannion, director of community relations for the Diocese of Camden who has counseled DiRenzo and her family.
Mannion says doing good for others can help make suffering redemptive, and DiRenzo and Blake Marchese agree.
"We can't fathom that he would pass away at age 26 for no reason," Marchese says.
"That's why I am trying to be there for people," DiRenzo says. "I'm on a mission."
Contact staff writer Kevin Riordan at 856-779-3845, firstname.lastname@example.org, or @inqkriordan on Twitter. Read the metro columnists' blog, "Blinq," at http://www.philly.com/blinq.