WHEAT RIDGE, Colo. -- The "slick" mess on Interstates 70 and 76 that caused several crashes on Monday is being blamed on an EDS Waste Solutions truck, according to Wheat Ridge police.

Wheat Ridge police said Tuesday the truck leaked treated waste, creating a half-mile long slick on the highway, officials said. The slick caused two motorcyclists to lose control and a number of car accidents on Interstate 70 near Ward Road. It also caused another crash on Interstate 76, according to the Colorado State Patrol.

Wheat Ridge police said the leak was caused by a gap in the bottom of the truck where the latch was not secured. It spilled when the load shifted.

Seven people were taken to the hospital, however officers said none of the injuries appeared to be serious.

Wheat Ridge police cited the driver, Victor Ward, of Arvada, for spilling a load on a highway. The Colorado State Patrol also cited Ward for a spilled load that caused injury.

7NEWS checked and found that Ward has twice pleaded guilty to driving a multi-axel with an overweight load.

In 2007, Ward was fined $2,112 for exceeding the maximum weight for a double-axel vehicle by 11,880 pounds in Clear Creek County, court records said. In 2006, he was fined $245 in the same county for exceeding the maximum weight for a tandem-axle vehicle by 6,060 pounds.