Auditors in New York say some drugmakers and pharmacists have a bad habit of flushing unneeded pills down the drain.
State Comptroller Thomas DiNapoli says this kind of drug disposal can lead to dangerous soil and groundwater contamination.
A state audit found that over 50% of controlled substances from 20 providers were flushed down the drain in recent years.
The state has been shifting away from flushing drugs since 2008. Environmental groups have long sought safer disposal regulations.
Despite the problems, the audit did find that the providers made the right decision to dispose of the drugs — instead of pushing a surplus of unneeded drugs, including painkillers, into the market.