According to the website for Turner's company, Aspen MLT, the artist passed away on June 27, 2008, at approximately
10:42 pm in Santa Monica, CA.
Before starting his own company, Turner was best known for his work on Witchblade, Superman/Batman, as well as creating variant covers for Marvel's Civil War and DC's Identity Crisis mini-series. Turner also created covers for titles such as Wolverine: Origins and World War Hulk. Earlier this month Marvel had just released images of his variant for Uncanny X-Men #500.
Aspen's website encourages fans to send their condolences to Michael Turner's via the following address: Aspen MLT, Inc., C/O Michael Turner, 5855 Green Valley Circle, Suite 111, Culver City, CA, 90230