Indeed, the International Energy Agency estimates that the additional precautions needed to ensure shale-gas wells’ environmental safety – including careful attention to seismic conditions, properly sealed shafts, and appropriate waste-water management – add only about 7% to the cost.
事实上，据国际能源署估计，确保页岩气井的环境安全性所需要的附加预防措施——包括密切关注地震条件、合适的密封通风井以及合理的废水管理等——只会带来7%的额外成本。