ALBUQUERQUE, N.M. (AP) — U.S. Surgeon General Vivek Murthy is calling for more investment in addressing the nation’s opioid epidemic, saying only half of the 2 million people who need drug treatment in the country have access to it.

Murthy’s comments Tuesday come after his tour of a substance abuse center in New Mexico, a state that federal data show had one of the nation’s highest overdose death rates in 2014.

Murthy says the Department of Health and Human Services is investing in the expansion of treatment centers, like the one he visited in Albuquerque.

Overdose deaths remain New Mexico’s leading cause of injury death.

Murthy’s Albuquerque visit follows a tour he took Monday of the Community Bridges Central City Addiction Recovery Center in Phoenix.