These emulsifiers are able to wrap around water soluble chemicals and suspend them in an oil-based solution. When mixed with water, the oil and herbicide are suspended in the water, and like the aqueous solutions mentioned above, can separate if not properly agitated. Care must be taken when tank mixing emulsifiable concentrates with other chemicals because there can be incompatabilities that can lead to the chemicals forming a sludge that neutralizes the chemicals and seriously clogs the sprayer. Unless clearly stated otherwise on their label, all liquid formulations should be protected from freezing. There are some exceptions, with Roundup Pro being an example of a product that can freeze and thaw repeatedly with no loss of activity.
Liquids also have a shorter shelf life than dry products.
Except for the water soluble products, they can separate into phases in the containers that may or may not remix. Liquid or aqueous solutions may separate into a liquid and solid phase, with the solid phase accumulating on the bottom of the container. If stored too long, it may be impossible to properly mix them again even with vigorous agitation. Emulsifiable concentrates are less likely to separate, but may do so if stored too long. Buy only as much herbicide as you should need in one year.