Injectable stem packing systems allow emergency sealing if primary packing is damaged. A lantern ring with two injection ports is positioned between upper and lower packing stacks. High-viscosity compound is pumped in at up to 10,000 psi to form a temporary seal. API 6A requires that injectable systems be capable of holding full-rated pressure for at least 30 minutes after injection https://globalsealstech.com/product-category/oil-gas-seals/api-6a-gate-valve-seals/