External stem seal leakage creates visible ice formation, measurable fugitive emissions contributing to environmental impact, potential personnel exposure to cold burns if leaking cryogenic product contacts skin, and flammable vapor clouds if leakage rates are sufficient and atmospheric conditions promote vapor accumulation near grade level where ignition sources might be present https://globalsealstech.com/product-category/oil-gas-seals/api-6d-ball-valve-and-lng-seals/