Maneb is a fungicide.
Maneb may have properties of spontaneous combustion. Its classified as Class 4.2 with subsidiary risk class 4.3 ( substances liable to spontaneous combustion/substances when in contact with water emits flammable gases or, when stabilized, classified as 4.3 substances when in contact with water emits flammable gases
When maneb is not having self-heating properties then it can be classified under class 4.3; however this must be proved by a lab test report that a cubic volume of 1 m³ of substance does not self-ignite and that the temperature at the centre of the sample does not exceed 200 °C when the sample is maintained at a temperature of not less than 75 °C ± 2 °C for a period of 24 hours and shipment must be accompanied by a certificate from shipper that the substance does not belong to class 4.2.