FuelClear™ MB15 Fuel Biocide is a high-performance antimicrobial agent (microbicide) from Fuelcare, developed specially to combat the problems of microbial contamination and spoilage in hydrocarbon fuels.


FuelClear™ MB15 is effective at low use levels, against microbial species commonly encountered in fuel systems, including bacteria, yeast, and mold. FuelClear™ MB15 is designed to cause inhibition of microbial growth upon contact, and quickly result in cell death. FuelClear™ MB15 is effective in systems containing both fuel and water. Unlike other fuel treatment biocides, the active ingredients in FuelClear MB15 are not deactivated by water.

FuelClear™ MB15 contains an active ingredient of 5-chloro-2-methyl-3(2H) isothiazolone and 2-methyl-3(2H) isothiazolone (C.M.I.T./M.I.T.) in a 3:1 mixture ratio. FuelClear MB15 is a solution of the technical grade of the active ingredient, C.M.I.T./M.I.T. in Dipropylene Glycol at a nominal value of 1.5% of active substance. Both active ingredient and tradename (FuelClear™ MB15) have been notified and approved under the E.U. Biocides Products Regulations (B.P.R.).

Professional Users Only. Use biocides safely. Always read the label and product information before use.



Always use FuelClear™ MB15 in accordance with local regulatory requirements (i.e. E.U. Biocides Products Regulations) and O.E.M. guidelines, and do not exceed recommended dose levels. Extreme care must be taken to avoid the addition of a preventative/maintenance level dosage of FuelClear™ MB15 to a heavily contaminated fuel system.

The biocide should be added in such a manner so as to allow good mixing and uniform distribution of the biocide across the fuel. Ideally, FuelClear™ MB15 should be dosed into a flowing fuel stream in the storage tank inlet – please contact Fuelcare for suitably approved dosing systems. Other methods of application, such as bulk dosing, will not affect the performance FuelClear™ MB15, but might extend the treatment time required. Tanks must be at least 10% full before dosing and preferably fill the tank after dosing. Do not dispense into empty fuel tanks.

Where possible, water and sludge should be removed from fuel tanks before dosing FuelClear™ MB15 and also after the retention period. If this is not feasible, filters should be checked more frequently for a short period, due to microbial slimes being killed off and dislodged. FuelClear™ MB15 is not surface active and therefore will not inhibit water separation.

At 300ppm a minimum retention time of 12 hours should be maintained but this may be reduced at the higher dosage rates. In general, the higher the concentration of biocide, the shorter the contact time required for a more complete kill but in all cases 24 hours retention is sufficient. The higher dosage rates in these circumstances will also help to improve filter fuel flow in the short term.


Features and Benefits 

Treatment with FuelClear™ MB15 will kill off bacterial and fungal contamination and assist the breakdown of slimes and coagulated biological sludges. This will help to prevent filters from blinding, and allow clean fuel to flow normally.

An extra advantage is the elimination of the often deep emulsion layer at the fuel/water interface which will facilitate water removal by draining or by the fuel line separator. It is this emulsion that is often the critical problem when it enters the fuel line after fuel contents of a tank are disturbed or shaken.

Fuel treated with FuelClear™ MB15 will remain protected from contamination over extended periods of time. It will also resist contamination if re-inoculated from other sources.