Visible crew/equipment: When asking the street gang in the street war sequence to drop their weapons ("I am the law") you can clearly see the cable the microphone is connected to running from the back of Stallone's helmet. This cable is not visible before or after.
Visible crew/equipment: As Hershey and Dredd deal with the driver in the red car, the film crew and equipment can be seen in their helmets.
Visible crew/equipment: When Dredd is done judging the motorist, blows the car up, and says "Happy motoring!" the squad comes to arrest him. When the camera is looking at him, you can see an overhead camera rig reflected in his visor.
Answer: The facility only ever cloned Rico and Dredd. It had never been tested at max capacity. The equipment was also 30 years old and Rico tried to birth the clones early which the system wasn't designed for. The stress of all these things added up to destroy it.
Grumpy Scot