PowerCLI to write zeros to all drives for multiple VM's

All,

For security we are required to write zero our VM HD's when decommissioning them. I would like to use a PowerCLI script to do this. The only way I know to do this is by logging into the host and running vmkfstools -w [path to vmdk file]. Unfortunately, I have to wait until one drive is done before I can start on another. If there is a simpler way within the CLI or if anyone has a script that would be helpful.

Thanks!