DOVER — Mandatory expungements for some individuals convicted of possessing or using small amounts of marijuana before the state decriminalized pot in 2015 became law Wednesday with Gov. John Carney’s signature.

But, the measure only applies in instances where the marijuana charge is a person’s only criminal conviction.

An expungement seals a criminal record, effectively erasing the conviction.

“As a supporter of criminal justice reform, this is common sense legislation to provide equity for those previously convicted of offenses that are no longer illegal,” Senate Minority Whip Greg Lavelle, a Sharpley Republican who was the bill’s main sponsor, said in a statement.

“The narrow scope of this legislation provides relief specifically to those with no other criminal convictions. This will expedite these expungements without overburdening the system.”

In order to receive an expungement, an affected individual must request his or her certified record from the State Bureau of Identification. At that point, he or she can pay a fee and fill out a form to fill out to apply for a mandatory expungement.

The measure, Senate Bill 197, does not apply to people convicted for using or having more than 1 ounce of cannabis. Lawmakers decriminalized possession of 1 ounce or less three years ago.

According to the Office of Defense Services, between 500 and 700 people are eligible under the bill.

“A criminal record is a barrier to gainful employment, stable housing, and further education,” Lisa Minutola, chief of legal services for the Office of Defense Services, said in a statement.

“As we have said in the past, Senate Bill 197 is an equitable fix to an arbitrary barrier that was created following decriminalization in 2015. We can now help individuals expunge their record and move on from a mistake.”

The legislation passed with no opposition, unlike a bill to legalize marijuana, which failed in the House in June.

Several states have passed legislation sealing misdemeanor marijuana convictions, and others have proposed expungement measures.