Question: What chemical compound caused the industrial disaster in Henderson, Nevada on May 4, 1988?
Context: An aroma compound, also known as an odorant, aroma, fragrance, or flavor, is a chemical compound that has a smell or odor.  A chemical compound has a smell or odor when it is sufficiently volatile to be transported to the olfactory system in the upper part of the nose. The West Pharmaceutical Plant explosion was an industrial disaster that occurred on January 29, 2003 at the West Pharmaceutical Plant in Kinston, North Carolina, United States.  Six people were killed and thirty-six people were injured when a large explosion ripped through the facility.  Two firefighters were injured in the subsequent blaze.  The disaster occurred twelve years and 170 mi from the 1991 Hamlet chicken processing plant fire, America's second-worst industrial disaster. In chemistry, a chemical compound, or simply a compound, is a molecule (or molecular entity) composed of atoms of more than one element, that are associated via chemical bonds; or a corresponding chemical species, which is a pure chemical substance composed of many identical such compound molecules.  There are four types of compounds, depending on how the constituent atoms are held together: molecules held together by covalent bonds, ionic compounds held together by ionic bonds, intermetallic compounds held together by metallic bonds, and certain complexes held together by coordinate covalent bonds.  Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service (CAS): its CAS number. Potassium alum, potash alum, or potassium aluminum sulfate is a chemical compound: the potassium double sulfate of aluminium.  Its chemical formula is KAl(SO) and it is commonly found in its dodecahydrate form as KAl(SO)·12HO.  Alum is the common name for this chemical compound, given the nomenclature of potassium aluminum sulfate dodecahydrate.  It is commonly used in water purification, leather tanning, dyeing, fireproof textiles, and baking powder.  It also has cosmetic uses as a deodorant, as an aftershave treatment and as a styptic for minor bleeding from shaving. In organic chemistry, a saturated compound is a chemical compound that has a chain of carbon atoms linked together by single bonds. Alkanes are saturated hydrocarbons.  An unsaturated compound is a chemical compound that contains carbon-carbon double bonds or triple bonds, such as those found in alkenes or alkynes, respectively.  Saturated and unsaturated compounds need not consist only of a carbon atom chain.  They can form straight chain, branched chain, or ring arrangements.  They can have functional groups, as well.  It is in this sense that fatty acids are classified as saturated or unsaturated.  The amount of unsaturation of a fatty acid can be determined by finding its iodine number. Pangamic acid, also called pangamate, is the name given to the chemical compound described as "-gluconodimethylamino acetic acid", initially promoted by Ernst T. Krebs, Sr. and his son Ernst T. Krebs, Jr. as a medicinal compound for use in treatment of a wide range of diseases.  They also termed this chemical "Vitamin B", though it is not a true vitamin, has no nutritional value, has no known use in the treatment of any disease and has been called a "quack remedy".  Although a number of compounds labelled "pangamic acid" have been studied or sold, no chemical compound, including those claimed by the Krebses to be pangamic acid, has been scientifically verified to have the characteristics that defined the original description of the compound. Ammonium perchlorate ("AP") is an inorganic compound with the formula NHClO.  It is a colorless or white solid that is soluble in water.  Perchlorate is a powerful oxidizer and ammonium is a good fuel.  This combination explains the usefulness of this material as a rocket propellant.  Its instability has involved it in a number of accidents, such as the PEPCON disaster. A lead compound (i.e. a "leading" compound, not lead metal) in drug discovery is a chemical compound that has pharmacological or biological activity likely to be therapeutically useful, but may still have suboptimal structure that requires modification to fit better to the target.  Lead drugs are followed by back-up compounds.  Its chemical structure is used as a starting point for chemical modifications in order to improve potency, selectivity, or pharmacokinetic parameters.  Furthermore, newly invented pharmacologically active moieties may have poor druglikeness and may require chemical modification to become drug-like enough to be tested biologically or clinically. The PEPCON disaster was an industrial disaster that occurred in Henderson, Nevada on May 4, 1988 at the Pacific Engineering and Production Company of Nevada (PEPCON) plant.  The conflagration and subsequent explosions killed two people, injured 372 others, and caused an estimated US$100 million of damage.  A large portion of the Las Vegas Valley within a 10 mi radius of the plant was affected, and several agencies activated disaster plans. In chemistry, the empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound.  A simple example of this concept is that the empirical formula of sulfur monoxide, or SO, would simply be SO, as is the empirical formula of disulfur dioxide, SO.  This means that sulfur monoxide and disulfur dioxide, both compounds of sulfur and oxygen, will have the same empirical formula.  However, their chemical formulas, which express the number of atoms in each molecule of a chemical compound, will not be the same.
Answer: Ammonium perchlorate