Trash-mapping expedition sheds light on 'Great Pacific Garbage Patch'

• Volunteers investigate collection of waste some say is twice the size of Texas
• Most trash seen in larger chunks, prompting call for urgent cleanup

Scientists and volunteers who have spent the last month gathering data on how much plastic garbage is floating in the Pacific Ocean returned to San Francisco on Sunday and said most of the trash they found is in medium to large-sized pieces, as opposed to tiny ones.

Volunteer crews on 30 boats have been measuring the size and mapping the location of tons of plastic waste floating between the west coast and Hawaii that according to some estimates covers an area twice the size of Texas.