The pulp and paper industry contributes to the economic development of the U.S., producing goods that meet primary needs. However, this sector must operate in a balance with the environment to ensure ecological preservation. Proposing a non-radial slacks-based measure – data envelopment analysis (SBM-DEA) approach, this study assessed the environmental efficiency of the pulp and paper industry in the U.S. from 2015 to 2018. External environmental impacts and random interferences on efficiency assessment were explored by using a stochastic frontier approach (SFA) regression. This study revealed that the U.S. pulp and paper industry was highly non-eco-efficient in the period evaluated, presenting an average environmental efficiency value of 0.509. Also, it is suggested that a total of 2.967 million metric tons of CO2eq emissions were in excess of those that were estimated based on an assumption of perfect environmental efficiency from 2015 to 2018 in the U.S. pulp and paper Industry. Based on the analysis of input and output slacks and the external environmental factors which reflect the environmental features of each decision-making unit (DMU), these facilities should substantially reduce CO2eq emissions and enhance the resources-allocation efficiency for improving the environmental efficiency of the U.S. PPI.