An overdose of Ecstasy killed a 24-year-old San Leandro man at the Electric Daisy Carnival in Las Vegas last month, authorities said.

The Clark County Coroner's Office confirmed that Montgomery Tsang died from "acute MDMA toxicity" after collapsing outside the Las Vegas Motor Speedway just after 6 a.m. on June 21. MDMA is the active ingredient in Ecstasy, a drug often associated with raves and electronic dance music.

Tsang's heart also was enlarged, the coroner said.

The death was at least the second associated with Ecstasy at the multiday music festival since 2010, according to the Los Angeles Times. A 15-year-old girl died from an Ecstasy overdose that year, leading to the concert's relocation from Los Angeles to Las Vegas.

The concert features DJs and was expected to draw close to a half-million people this year.

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rderh