"Different refineries might actually be blending ... involved mixing an SS-1-type anionic asphalt emulsion, (the same type of emulsion commonly used on paving tack coats today) with coal tar ...

In a water-in-oil emulsion, the continuous phase is oil. Emulsifiers make both types of emulsions. Milk is the perfect example of a natural oil-in-water emulsion. The oil in the milk is suspended ...