Many adolescents and young adults hold erroneous beliefs that cigarillos and waterpipe tobacco (WT) are safer than cigarettes, contributing to use. Communication campaigns can correct misperceptions and increase risk beliefs. We tested point-of-sale (POS) communication campaigns focused on chemical exposure for cigarillos and WT. We conducted two cluster randomized trials at 20 gas stations with convenience stores (10 stores for cigarillos, 10 for WT) in North Carolina between June and November 2017. Within each trial, stores were randomly assigned to either the intervention (campaign messages displayed) or a no message control condition. We conducted intercept surveys with repeated cross-sectional samples of 50 adolescents and young adults (ages 16-25) per store, at baseline and follow-up. There were 978 participants (mean age = 20.9 years) in the cigarillo trial, and 998 participants (mean age = 21.0 years) in the WT trial. Rates of campaign exposure were low (26% for cigarillos; 24.3% for WT). The cigarillo campaign increased knowledge that ammonia is in cigarillo smoke (p < .01). There were also significant increases in knowledge about ammonia and cyanide in cigarillo smoke and arsenic in WT smoke (p < .05) in the sub-sample who reported exposure to the campaign. No differences were found in outcome expectancies, product attitudes, worry about chemical exposure, or behavioral intentions in either campaign. Garnering attention for communication campaigns in saturated POS environments, often dominated by tobacco advertising, is challenging. Our study demonstrates the feasibility of anti-tobacco campaigns at the POS and points to several lessons learned for future POS campaigns.