The effect of the thermally expanding flame retardant dosage as well as its combination with the modifier - the product of silicone rubber waste destruction - on the properties of cold-cured compositions based on low-molecular-weight silicone rubber was studied. It was shown that equal mass substitution of aluminum hydroxide for thermally expanding graphite in an amount of 5% by weight results in sealants with a swelling ratio of 5.8, which is sufficient for fire retardant systems used in nuclear and thermal power plants. It was established that the use of an optimal amount of destructive material (5% by weight) in combination with thermally expanding graphite leads to an increase of the conditional strength at break of silicone flame-resistant cold-curing compositions by 35%. The use of thermally expanding graphite and the silicone waste destruction product in the formulation of a silicone sealant reduces the cost of the composites obtained by 6% in terms of raw materials.