In New York, the decision over whether to lift a ban on the gas-drilling process known as “fracking” is facing a delay after regulators studying its health impact said they needed more time to complete a key review. The move could potentially delay the rule-making process for months, leaving the ban in place. On Tuesday, the state’s top environmental regulator said he may speed up the process by issuing permits for fracking before final regulations are created if the health department concludes the process is safe. Critics say fracking, which involves blasting liquid into deep underground rock, threatens the environment, water supplies and public health.