In 2017, Puerto Rico sustained extensive damage from Hurricane Maria, increasing the risk of fires and carbon monoxide (CO) poisonings. Using a population-based, in-person survey of households with children less than 6 years old in Puerto Rico, we collected data in 2010 concerning the presence of smoke alarms and CO alarms in these households. We generated national estimates by extrapolating the number of households in each stratum using data from the 2010 Census. We determined which household characteristics predicted the presence of these alarms. Of 355 households analyzed, 31% had functional smoke alarms, or an estimated 109,773 households territory wide. The presence of smoke alarms was associated with living in multifamily housing and no child in the household receiving government medical insurance. Public housing or publicly subsidized housing, as compared to owner-occupied housing and unsubsidized rental housing, was associated with having a functional smoke alarm in households with children aged less than 6 years. Based on only six houses having CO alarms, we estimated only 7685 (2%) households had CO alarms. The low prevalence of functional smoke or CO alarms 7 years before Hurricane Maria is unfortunate and should be remedied by ensuring that such alarms are widely installed in current rebuilding activities.