染色物质 meaning in English

combination backing

Marked oil , commonly called " red " oil , is light diesel oil to which a prescribed marker ( a specified chemical ) and colouring substance have been added
有标记油类，一般称作“红油” ，是一种加入规定标记， (一种指定的化学品)和染色物质的轻质柴油。
The existence of the colouring substance and the prescribed marker provides ready identification aids and facilitates customs officers in detecting the illegal use of marked oil as fuel for road vehicles
所加入的染色物质及规定标记能有助海关人员侦查非法使用有标记油类作燃料的车辆。