After the cut scene of you getting a idea on how to get under Maero’s skin,(This whole mission is timed, so move fast!) go to a local Friendly Fire and buy a Geiger Counter. Once you have purchased the Geiger Counter head to the nuke plant (Driving to a boat and driving the boat to the nuke plant).
Once at the nuke plant start looking for toxic waste, this is were the Geiger Counter comes in handy, a bar that says radio activity should appear and will start moving when you are getting close to the toxic waste, the bigger the bar the closer you are (You must find the toxic waste without getting caught). Once you have the toxic waster make your way to the helipad, at the helipad kill all the guards so that the helicopter can land. Once the helicopter has landed get in and start shooting at any police you see.
When you are close enough to the land Carlos will inform you that you are going to crash! Once you have recovered from the crash get to the closest car you can find and deliver it to the tattoo parlor (Don’t forget Carlos). Once you have made it to the tattoo parlor the mission is over.