Lego Batman 2: DC Superheroes Walkthrough Part 13 – Chemical Crisis, Part 1

Road to Ace
At Arkham, take a moment to use the Batcomputer's remote terminal. Captain Boomerang is revealed to be a boss at the South end of the island of Arkham. The other important part is farther South from Arkham is Ace Chemicals. It has been marked already for you.

Leave on the road away form Arkham to the barrier in front of Gotham City. Stop there and hop out of the car. To the left you will find an electrified generator and farther left, the Electricity Suit. Get into the suit and draw the power out of the generator. That will clear the way forward for you.

Follow the phantom chips to the first right and turn there. Keep on this street to the T-intersection, turn left there followed by making the first right. Follow this with another left and another right. Just follow that path to Ace Chemicals.

Chemical Crisis
Switch to Robin and have him get into the Hazard Suit that is over to the right. You need to first destroy the nearby boxes to reassemble them as the switch that will open the tube around the suit changer. You need to throw the switch twice to get to open the tube. Get into the hazard suit then head over to the right and up the stairs into the Water Tank in the back of the room.

Fall into the left-hand half of it. There you will find a switch that will raise the nearby tank from the depths of the water. Once it is up and out of the water, have Robin climb over to it. From there jump up onto the bar and again jump to reach the maxed out tank. Interact with the tank to finish matters in this area, summon 3 of Joker's Henchmen to attack you. Fill up Robin tank and head over to the right.

Follow the Catwalk to the right, dealing with the Henchmen that are attacking you. Use the Batarang on any that are above you and causing a lot of harm. Otherwise, just press forward to the right.

At the opposite end of the catwalk, just to the right of the stairs off it is a wheel valve. Spin it to reveal a Suit Changer buried under chemicals. Have Robin clear it off with the Hazard Suit's sprayer. Change to Batman and have him don the Electricity Suit. Head for the arcing ladder in the back left and have Batman climb up it. At the top is the generator powering it. Have him draw the power over to himself then head for the catwalk the henchmen were attacking you from, on the left. At the other end of the catwalk you will find the second generator you need to shut down. Just head over to it and interact with it.

Time to head over to the right and jump into the water pipe with Robin. Head to the right with him and throw the switch in the second part of it to drain the water. This clears the way for Batman who will automatically follow along.

Head over to the right and down the stairs to the level below you. There you can use the Hazard Suit's water to clear away the large pile of chemicals in the top left corner of the area. It will reveal the Magnetic Suit for Robin to use. In the bottom right corner of this area you will find a pool of water that can be used to refill the Hazard Suit's tank if needed.