Birch tar oil with CAS number of 8001-88-5 is also named as Birch oil ; Birchtaroil,empyreumatic ; Birchtaroil,rectified ; Essentialoilofbirchwood ; Oils,birch-tar ; oils,whitebirch ; Oilwhitebirch;oleumrusci ; Gaultheriaoel ; Wintergruenoel ; Flucarmit ; Analgit ; Exagien ; Betula ; Gaultheria oil ,and so on. Birch tar oil (CAS No.8001-88-5) is usually dark brown liquid.
IUPAC Name: Methyl 2-hydroxybenzoate
CAS: 8001-88-5
Molecular Formula:  C₈H₈O₃
Molecular Weight: 152.1473
Molecular structure:
ACD/LogD (pH 5.5): 2.23 
ACD/LogD (pH 7.4): 2.23 
ACD/BCF (pH 5.5): 29.38 
ACD/BCF (pH 7.4): 29.25 
ACD/KOC (pH 5.5): 391.25 
ACD/KOC (pH 7.4): 389.57 
H bond acceptors: 3 
H bond donors: 1 
Freely Rotating Bonds: 3 
Index of Refraction: 1.547 
Molar Refractivity: 39.9 cm³ 
Molar Volume: 125.7 cm³ 
Polarizability: 15.82×10^-24cm³ 
Surface Tension: 45.7 dyne/cm 
Density: 1.209 g/cm³ 
Flash Point: 86.8 °C 
Enthalpy of Vaporization: 47.71 kJ/mol 
Boiling Point: 222 °C at 760 mmHg 
Vapour Pressure: 0.07 mmHg at 25°C 

 Birch tar oil (CAS No.8001-88-5) is commonly used in the creation and/or manufacturing of fragrance concentrates of all types.

Reported in EPA TSCA Inventory.

A skin irritant. Moderately irritating to eyes and mucous membranes. A mild allergen. Combustible when exposed to heat or flame; can react with oxidizing materials.

Hazard Codes:  Xi
Risk Statements:  36/37/38 (R26/27/28:Very toxic by inhalation, in contact with skin and if swallowed.)
Safety Statements:  26-36 (S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36:Wear suitable protective clothing.)
WGK Germany:  3
RTECS:  DW3000000

Removal in wastewater treatment of  Birch tar oil (CAS No.8001-88-5) can be stated as follows:
Total removal:7.87  percent
Total biodegradation:0.10  percent
Total sludge adsorption:3.04  percent
Total to Air:4.73  percent
(using 10000 hr Bio P,A,S)