IUPAC Name: Furo[3,4-f][2]benzofuran-1,3,5,7-tetrone
Molecular Formula: C₁₀H₂O₆
Molecular Weight: 218.119280 g/mol
Appearance: White powder
Melting Point: 283-286 °C(lit.)
Boiling Point: 397-400 °C(lit.)
Flash Point: 380 °C
Density: 1,68 g/cm³   
Water Solubility: Decomposes
Sensitive: Moisture Sensitive
Structure of 1,2,4,5-Benzenetetracarboxylic anhydride (CAS NO.89-32-7):
                          
Product Category of 1,2,4,5-Benzenetetracarboxylic anhydride (CAS NO.89-32-7): Intermediates of Dyes and Pigments;Benzene derivates;Functional Materials;Reagent for High-Performance Polymer Research

 1,2,4,5-Benzenetetracarboxylic anhydride (CASNO.89-32-7) is used for making polyimide resin, high temperature electrical insulating paint, PVC plasticizers, cross-linking agent of synthetic resin and curing agent of epoxy resin.

 1,2,4,5-Benzenetetracarboxylic anhydride (CAS NO.89-32-7) hasn't been listed as a carcinogen by NTP, IARC, ACGIH, or CA Prop 65. You can see actual entry in RTECS for complete information.

Reported in EPA TSCA Inventory.

Poison by inhalation. Moderately toxic by ingestion. When heated to decomposition it emits acrid smoke and irritating vapors.
Hazard Codes: Xn 
Risk Statements: 41-42/43
41:Risk of serious damage to eyes
42/43:May cause sensitization by inhalation and skin contact   
Safety Statements: 22-24-26-37/39
22:Do not breathe dust   
24:Avoid contact with skin  
26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice 
37/39:Wear suitable gloves and eye/face protection 

 1,2,4,5-Benzenetetracarboxylic anhydride , its cas register number is 89-32-7. It also can be called Pyromellitic dianhydride ; Benzene-1,2,4,5-tetracarboxylic dianhydride ; PMDA ; and Pyromellitic acid dianhydride . It is hazardous, so the first aid measures and others should be known. Such as: When on the skin: first, should flush skin with plenty of water immediately for at least 15 minutes while removing contaminated clothing. Secondly, get medical aid. Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Then get medical aid soon. While, it's inhaled: Remove from exposure and move to fresh air immediately. Give artificial respiration while not breathing. When breathing is difficult, give oxygen. And as soon as to get medical aid. Then you have the ingesting of the product: Wash mouth out with water, and get medical aid immediately. Notes to physician: Treat supportively and symptomatically.
In addition, 1,2,4,5-Benzenetetracarboxylic anhydride (CAS NO.89-32-7) could be stable under normal temperatures and pressures. It is not exposured to moist air or water, and you must not take it with incompatible materials. And also prevent it to broken down into hazardous decomposition products: carbon monoxide, carbon dioxide.