The deepwater horizon accident may have shaken the sustainability ratings and indices credibility, but it also reinforced their importance. The objective of this article is to contribute to the improvement of corporate sustainability valuations by investigating if reserves profiles can affect the environmental risk exposure of an Oil & Gas (O&G) corporation. Data on reserves from 2009 to 2012 of 24 listed O&G companies were used to test six hypotheses, addressing how these profiles could relate to the four material environmental risks: climate change, accidents, sensitive area/access, water. The frequency with which companies reported these risks was evaluated using key word in context (KWIC) content analysis. Analysis of variance (Anova) and Student's t tests were applied to each of the hypotheses. This study shows environmental risks are embedded with the oil and gas reserves. We found the following relationships: (1) companies with heavy oil reserves report more exposure to climate change risks, particularly emissions control; (2) water is more of an issue with companies with higher bitumen and natural gas reserves; and (3) there is significant regional bias in the reporting of the environmental risk factors. These findings have broad implications for the financial industry, governments, investors and lenders alike. (C) 2014 Elsevier Ltd. All rights reserved.