The Sudbury Action Centre for Youth, known as SACY, started offering testing of illicit drugs earlier this year to help curb overdoses.
Officials say the test to detect fentanyl and carfentanil is working, but there are concerns the testing method cannot detect other chemicals some street drugs may be cut with.
SACY says it's now looking at new testing methods to detect the harmful and lethal substances.
Sudbury police confirm there were eight overdose deaths in 15 day period in February of 2019.
