Poisoning from Carbon Monoxide (CO) is among the leading causes of non-fatal injuries treated in US hospital emergency departments and accounts for approximately 500 unintentional deaths each year. Known effective countermeasures to detect CO and reduce CO poisoning exist, yet are not routinely utilized. Although there is increasing concern about the need to increase CO detector use, little is known about how best to do so, especially for low income families. This research aims to address this gap, by applying a theory of stage-based behavior change—the Precaution Adoption Process Model PAPM)—to a brief intervention feasible for a busy emergency department setting. A randomized trial will be conducted involving 300 families with children 18 years or younger. In the Pediatric Emergency Department (PED), eligible parents will randomly be assigned to receive the Project CODE intervention (an educational tool and a CO detector) or usual care (a flyer on CO poisoning). The use of a CO detector and participant's PAPM stage will be assessed at enrollment and again at follow-up home visits occurring two-weeks and six-months following the PED visit. We hypothesize that parents receiving Project CODE will have working CO detectors and will be further along in the PAPM than parents in the control group at a two-week and six-month follow-up home visits. By examining the extent to which the intervention increases CO detector use, these findings will also demonstrate how innovative health communications (brief interventions delivered in the PED) can reduce the risk of injuries among vulnerable children. This research builds on and extends the investigators' previous work on behavioral theory, injury prevention interventions delivered in the PED, and development and evaluation of interactive educational tools for safety practices. The specific aims of this project are as follows: Aim 1—Determine whether a brief intervention will increase CO detector use and PAPM stage among parents whose children are being seen in a PED compared to parents of children receiving routine care CO flyer; and Aim 2—Determine whether and to what extent socioeconomic status moderates the effect of the intervention. Findings from this research study will have both theoretical and practical applications for improving injury prevention services in PEDs. This single-site efficacy trial is the first step in determining whether a brief intervention in the PED will successfully increase CO detector use.