Original (Earth 1-2)
First appearing in Detective Comics #168, the Ace Chemical plant was a chemicals manufacturing facility located directly beside the Monarch Playing Card Company. The Playing Card Company was robbed by the professional criminal known as the Red Hood who was confronted by Batman. Red Hood attempted to escape through the ACE Chemical Plant and jumped into a vat of chemicals in order to escape and swam away from the vigilante through the use of a breathing device hidden within his signature cowl. After finally having made his escaping and taking refuge in the Playing Card factory, Red Hood noticed that the chemicals had bleached his skin bone-white, dyed his hair green and coloured his lips red. Noticing his similarities to the figure on Monarch's Joker playing cards, Red Hood declared himself "The Joker" and used his new appearance for a new life of crime.
According to a memory of the Joker which may or may not be true, before he was a super-criminal he was an employee at the Ace Chemical Processing Plant where he was a minor engineer with a mind for chemistry. He eventually quit his job to try and become a stand-up comedian only to fail miserably than later learn his wife Jeannie was pregnant which would send them into greater financial problems than they already were in. Desperate, he made a deal with gangsters in which he would help them rob his old workplace of ACE Chemicals in exchange for money. The gangsters gave him a red cowl made of one-way glass and a red cape, informing him that he'd be wearing both to disguise himself as "The Red Hood" a criminal alias which the gangsters used as a red herring to make the police (and Batman) focus on him while they were merely treated as accomplices. Not long before the robbery the engineer's wife and unborn child both died in a freak electrical accident when Jeannie tested out a defective electric baby-bottle heater. Forced to still go through with the crime, things turned sour when it was revealed the police and Batman ambushed them with the gangsters being shot down by police as the Red Hood was chased down by Batman who believed him to be a super-villain. Attempting to convince Batman he was simply a decoy, Red Hood attempted to remove the helm but tripped on his own cape and fell over edge of a cat-walk into a vat of chemicals where he was presumed deceased. In reality he was washed up in a chemical river and found himself with bleached white skin, dyed green hair and red-tinted lips. Finally being pushed off of the edge, the Red Hood became the Joker.
Years later the Ace Chemicals plant was the first location Batman came into contact with the new Red Hood, Jason Todd.
Prime Earth (New 52)
In the New 52, the plant is connected to Kane Chemicals, a company owned by the parents of Martha Wayne, which was then sold to Apex Chemicals, and then in turn became Ace Chemicals.
One night an insane super-villain known as the Red Hood attempted to use several chemicals and explosives to turn the entire ACE Chemicals Plant into a giant bomb with the help of his gang, the Red Hood Gang which was made up mostly of individuals black-mailed by the Red Hood. Red Hood was found out by the vigilante known as Batman who had only made a few appearances in Gotham prior to then but who had fought the Red Hood on countless occasions. Batman managed to prevent the plant from exploding but it was set aflame in the process, Red Hood attempted to escape via helacopter but Batman pulled him down to fight him hand-to-hand. Ultimately the fight ended with the cat-walk the two were fighting on being destroyed by a chemical blast from the over-heated chemical vat below. Red Hood was hanging off the edge of the cat-walk while Batman was securely on-top trying to save his enemy. Red Hood laughed at Batman's nobility and willingly let go, falling into the flaming vat of acid while smiling maniacally. Due to the acid having been lethal and boiling-hot Red Hood should have been killed by the fall and was presumed dead but his body was never found. The police had a suspicion from interrogations of Red Hood Gang members that the criminal's identity was a thug from the narrows named Liam Distal but Distal's body was found shortly after outside of Amusement Mile, dissolved in Lye so that the time and cause of death would be impossible to discover, presumably having been killed by the real Red Hood.
Some time later Red Hood resurfaced only now calling himself "The Joker" and having his skin bleached white and his hair dyed green.
Over the years, the Joker has revisited Ace Chemicals several times, and on occasion has even used it as a temporary hideout. Notable examples include Death of the Family, where Joker and Harley Quinn lure Batman to the Plant to repeat the "accident" that transformed the Red Hood into the Joker.
In other Media
In Tim Burton's Batman, the chemical factory appears in the form of Axis Chemicals. It combines Apex Chemicals and Ace to be the same place with a new name rather than siding with one or the other. The facility was owned by Gotham's don Carl Grissom who used it as a set-up to get rid of his mentally unhinged subordinate gangster Jack Napier due to him having an affair with Carl's mistress Alicia Hunt behind Carl's back. Carl had Jack and his men (including Bob Hawkins) break into Axis in order to steal documents from the safe which Carl told Jack the city's district attorney Harvey Dent wished to acquire as part of a legal case against Grissom's criminal empire. Jack took the job, but Carl then called the corrupt police Lieutenant Eckhart to find Jack and shoot him on sight. After raiding the safe and finding that they were no documents to take, Jack realised that he had been set up and told him men to be aware of any danger. Eckhardt and the police arrived and a massive gun fight took place while Jack escaped. Commissioner Gordon and some other policeman arrived and took over Eckhardt's operation. Hoping to capture Jack alive so they could also capture Grissom.
Jack meanwhile reached the top of the building and met Batman who hoisted him into the air. but after Bob held Commissioner Gordon at gunpoint, threatening to kill him, Batman let Jack go. Jack then shot Eckhardt dead and when Batman arrived again, he attempted to do the same to him. However the bullet ricocheted off the factory's machinery and struck Jack through the cheek. In pain and frightened, Jack fell off the catwalk that was above a huge vat of chemicals. Batman tried to pull him up, but he lost his grip and Jack fell into the vat.
The effect of the chemicals had bleached Jack's skin white, gave him green hair and red lips while also triggering his long repressed insanity. After receiving botched plastic-surgery for his bullet wound (which left Jack with a permanent smile), Jack became "The Joker", murdered Carl Grissom then took over the criminal empire for himself. Joker used Axis Chemicals to poison Gotham's food and cosmetics supply with Smylex, resulting in several deaths before the items he poisoned were recalled due to Batman. After this, Joker had the factory produce large amounts of lethal laughing gas which he put into giant parade balloons and led through downtown Gotham in a parade which he lured the citizens of Gotham to with the offer of free money. The factory was finally destroyed by Batman in his Batmobile via explosives and Joker's plan was foiled, ending in with his death and all his men either dead or captured.
The Ace Chemical Processing Plant briefly appears in the film Suicide Squad where the Joker tells his former therapist Dr. Harleen Quinzell who he had just tortured into obedience to jump into a vat of chemicals. Harley obeys (to Joker's surprise which is strange as he had already tortured her into obedience) so Joker decides to leave her in the vat (supposedly to die) but has a change of heart and leaps in himself. In the vat of chemicals, the Harley is now bleached white just like the Joker and the two kiss.
In the sequel Harley explodes the factory as part of her "emancipation."
DC Animated Universe
In Batman the Animated Series, Ace Chemicals was a chemical manufacturing plant which was robbed by the gang leader Jack Napier not long after he left the Valestra Mob. After Batman showed up to stop the robbery, Jack fell off of a cat-walk and into a vat of chemicals which transformed him into the Joker.
Years later Joker and his partner Harley Quinn began using Ace Chemicals as a criminal hideout. Upon falsely coming to believe that a low-level thug named Sidney "Sid the Squid" Debris had in-fact murdered the Batman, Joker held a funeral service for Batman at the chemical plant. Angry at Sidney having had supposedly killed Batman and taken away Joker's fun, Joker had Sidney locked inside of a coffin with Batman's cape then lowered into a vat of deadly acid. Sidney was saved however by the Batman.
Years after that, a reporter named Jack Ryder went to ACE Chemicals to do a piece on the Joker's origins but he was attacked by the Joker and pushed into the same chemicals which made Jack Napier into the Clown Prince of Crime while also being attacked with Joker Venom. The result of the combining chemicals transformed Jack Ryder into "The Creeper", a chaotic Tarzan-like person with super-strength who stalked Harley Quinn and attacked Joker before being returned to normal by Batman.
Ace Chemicals first appears in the episode A Dead Man Feels No Cold, in which Mr. Freeze raided the plant in order to steal supercooled liquid helium for his ice gun. During No Man's Land, Ace Chemicals was later taken over by Jeremiah Valeska, Ecco and the Mad Hatter, who used the factory to create toxic chemicals in a scheme to poison Gotham City.
An office-building location building for Ace Chemicals located in Old Gotham was one of many buildings shut off from public access upon the creation of Arkham City. Upon being imprisoned in Arkham City by Hugo Strange, Bruce Wayne climbs up the Ace Chemicals building and has his butler Alfred Pennyworth send a pod containing the bat-suit to the roof of the building.
In Interview-Tapes recording Hugo Strange's psychological interviews with the Joker, Joker tells a fabricated story about having once been a former low-level engineer at Ace Chemicals who quit to become a stand-up comedian only to discover his wife Jeannie was pregnant. Desperate, Joker made a deal with Gotham's don Carmine Falcone to aid in a robbery of Ace while disguised as a super-villain called the Red Hood which in reality was a red herring persona. In Joker's story, Batman stopped the robbery and Joker fell into a vat of chemicals which turned him into the disfigured clown he's known for being.
Contradicting Joker's story being confirmed as fabricated and his origins being unknown, the prequel game Arkham Origins features a flashback sequence in which Joker lives through a memory of being the Red Hood and falling into the vat of chemicals at Ace.
Long after the events of Arkham City, the ACE Chemicals Plant (here located on Bleake Island) was obtained by the Scarecrow through the Broker who had been hired to work for Scarecrow by Carmine Falcone for seemingly unknown reasons, possibly connected to the Falcone Crime Family being forced to leave Gotham to avoid incarceration in Arkham City. Scarecrow used to facility to manufacture enough fear-toxin to over-take the entire eastern seaboard. Batman found Scarecrow out and infiltrated the complex only to come into conflict with the Arkham Knight for the first time. Scarecrow rigged the facility to explode in a blast of fear-toxin but Batman managed to reduce to blast-radius although in the process he became infected with fear-toxin, triggering hallucinations of the (deceased) Joker.
Batman: The Telltale Series
Ace Chemicals is mentioned in several news reports in the first season. The plant is the site of a fire that takes serval days to put out. It is also mentioned that the chemical agent used by Thomas Wayne and the Children of Arkham was created at the plant.
In the second season, the Ace Chemicals Plant appears in final episode, Same Stitch. Now shut down for safety concerns, it is used as a hideout for the Joker and his gang, with access given from a former employee. If Joker is a vigilante, he interrogates Amanda Waller at Ace Chemicals and later battles Batman throughout the main mixing chamber. If Joker becomes a villain, Ace's facilities are used to mass produce Project LOTUS whilst its storage areas are used as part of a trap set for Batman.