Proppants are used in oil and gas extraction, particularly in fracking operations. The invention relates to resin coated proppants. The coatings on proppants have antimicrobial materials incorporated within these coatings. The antimicrobially active agents are incorporated in a concentration less than 20% by weight of the coatings or the active agent from these coatings can be released from these coatings in the environment of the proppants.