Enforcement Agency authorized increased production quotas for fentanyl, morphine, hydromorphone, codeine to meet COVID-19 treatment needs, as well as for methadone, to ensure addiction treatment centers are adequately supplied . Sludge concentrations of fentanyl, methadone, and hydromorphone increased during our study period (weekly samples, Figure ). Fentanyl and methadone are commonly used both legally and illegally. Hydromorphone is itself a drug, but it is also a metabolite of morphine, codeine, and other opioids, thus its increasing levels are an indication of overall increase in opioid concentrations . Levorphanol, an opioid used for pain management and as a preoperative drug , decreased in both daily and weekly sludge samples (Figure , Table ). This decrease is potentially due to the reduction in elective procedures during the study period . We did not observe trends over time for an additional four opioids (Table ). We note that our method was not capable of measuring heroin at these low concentrations (section S.2.1).