Empirical Formula: C₆H₇BO₃
Molecular Weight: 137.929
Nominal Mass: 138 Da
Average Mass: 137.929 Da
Monoisotopic Mass: 138.048825 Da 
Index of Refraction: 1.582
Molar Refractivity: 34.81 cm³
Molar Volume: 104.3 cm³ 
Surface Tension: 57.2 dyne/cm
Density: 1.32 g/cm³
Flash Point: 177.6 °C
Enthalpy of Vaporization: 65.08 kJ/mol
Boiling Point: 370 °C at 760 mmHg
Vapour Pressure: 3.95E-06 mmHg at 25 °C
Melting point: 210-213 °C (dec.)(lit.)
Appearance: White to light yellow crystal powder
Structure of 3-Hydroxyphenylboronic acid (CAS NO.87199-18-6):
                       
IUPAC Name: (3-Hydroxyphenyl)boronic acid
Canonical SMILES: B(C1=CC(=CC=C1)O)(O)O
InChI: InChI=1S/C6H7BO3/c8-6-3-1-2-5(4-6)7(9)10/h1-4,8-10H
InChIKey: WFWQWTPAPNEOFE-UHFFFAOYSA-N
Product Category of 3-Hydroxyphenylboronic acid (CAS NO.87199-18-6): Substituted Boronic Acids;Boronic Acids & Esters;Phenyls & Phenyl-Het;Organic acids;Aryl;Organoborons

 3-Hydroxyphenylboronic acid (CAS NO.87199-18-6) hasn't been listed as a carcinogen by NTP, IARC, ACGIH, or CA Prop 65. And the toxicological properties have not been fully investigated.

Hazard Codes: Xi
Risk Statements: 36/37/38
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 37/39-26 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S37/39:Wear suitable gloves and eye/face protection.

 3-Hydroxyphenylboronic acid , its cas register number is 87199-18-6. It also can be called (3-Hydroxyphenyl)boronic Acid . 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, 3-Hydroxyphenylboronic acid (CAS NO.87199-18-6) could be stable under normal temperatures and pressures. It is not compatible with strong oxidizing agents, light, and you must not take it with incompatible materials, acids, strong bases. And also prevent it to broken down into hazardous decomposition products: Carbon monoxide, carbon dioxide, boron oxides.