Catholic leaders say the move could bankrupt the church in the largely Catholic U.S. territory.
The bill, which does not apply to criminal prosecutions, was approved by the Legislature after abuse allegations surfaced against Archbishop Anthony Apuron.
Current Casa Grande resident Walter Denton publicly revealed he was molested as a child by Apuron when the archbishop was a Catholic priest in Guam.
The 52-year-old Denton told the Casa Grande Dispatch he attempted to report the incident almost 40 years ago, but nothing was done about it.
Denton held a press conference June 7 in Guam where he alleged he had been the victim of sexual abuse while serving as an altar boy at Our Lady of Mount Carmel Church, located in the village of Agat. He accused Apuron of raping him as a 13-year-old during a sleepover.
Three other victims have come forward, alleging they too were abused by Apuron.
Pope Francis appointed a Vatican official to temporarily take over Apuron’s position in the Agana Archdiocese as the claims are investigated.
Church leaders say lifting the statute of limitations would subject the church to unlimited financial liability, forcing the closure of parish churches and schools on the island where more than three quarters of Guam’s 162,000 residents are Roman Catholics.
Calvo acknowledged in an open letter to the people of Guam that he wasn’t sure if the measure’s retroactive application could withstand a legal challenge.
Apuron, now 70, has been accused of molesting at least five altar boys in the 1960s and 70s.
He has denied the allegations and hasn’t been charged with any crime.
His lawyer hasn’t returned repeated messages left by The Associated Press.
In response to the allegations, the Vatican appointed Archbishop Savio Hon as temporary apostolic administrator for Guam.
While in Rome discussing the matter, he sent a letter home urging parishioners to sign a petition against the bill.
In the letter, which priests read out loud during Mass on Sunday, he promised a canonical trial for Apuron.
Despite that, Hon issued a statement thanking the governor for his action, reiterating a Church apology to sex abuse victims, and pledging funds to help people who have suffered such abuse by clergy.
In the letter, Calvo said he was “saddened that even a single injustice had to happen in order to make this law necessary. There are no winners. Justice is the only victory.”
He added that he was resolute in his decision, saying the legislation opens “the doors of justice to those who suffered a terrible harm as children.”
Roland Sondia, 54, who also earlier this year publicly accused Apuron of molesting him when he was a 15-year-old altar boy, said he would now file a lawsuit.
“We all want justice,” he said.