In 2151, the Malurians were secretly mining the Akaalihomeworld for veridiumisotope using drilling equipment saturated with tetracyanate 622. The mining team was lead by Garos, who was disguised as an Akaali shopkeeper most of the time. Most of the other miners were also disguised as Akaali. The entrance to the mine was accessed through a secret passage in Garos' shop. (ENT: "Civilization")
In scripted but unused dialogue from "Civilization", Garos – while he is speaking duplicitously to Starfleetofficers from the NX-classstarshipEnterprise – states, "My people have very strict protocols when it comes to interfering with other species."
The return of the Malurians in "Civilization" was viewed, by Mike Sussman, as an amusing in-joke. "The Malurians are funny," he stated, "because they get wiped out by Nomad a hundred years later [in 'The Changeling'], so it was like, 'Wouldn't it be great to see these guys?' So we made them the bad guys in 'Civilization,' the green lizard guys – they get their comeuppance a hundred years from now!" 
In their natural appearance, the Malurians were scripted (in the script of "Civilization") to have "gray, scaly flesh."