This study investigates how firms respond to peers' environmental scandals, with a focus on their voluntary carbon disclosure decisions. Using the 2015 Volkswagen (VW) emissions cheating scandal as a case study, we analyze the voluntary carbon disclosures of automotive manufacturers in OECD countries. Our findings reveal an industry-wide reduction in voluntary carbon disclosures following VW's scandal. The effect is more pronounced for automakers lacking green patents, for those located in countries characterized by low levels of social trust, and for firms with less credible disclosed information. Our results are consistent with the interpretation that VW's emissions cheating represents a type of reputational damage that has broadly eroded public trust and raised doubts about the credibility of disclosures, leading firms with less credible information to be less likely to disclose voluntarily. Overall, these findings underscore the critical role of disclosure credibility in shaping decisions about voluntary disclosure.