The woman, whose name was not in the police report, was walking on the beach near the Beachtown subdivision when she saw a backpack rolling in the surf about 11 a.m. on May 22, Galveston police spokesman Jeff Heyse said.

She used her cell phone to call police, who discovered a black bag containing the cocaine bricks that weighed a total of 37 pounds 2 ounces. Each brick was marked with bar codes and wrapped in a rubber sheet, a large balloon and another plastic layer, Heyse said.

“There were barnacles growing on the bag so you know it was probably in the water a long time,” he said. He said the bricks were so wrapped so well that only four of the bricks had been contaminated by seawater.

The bag contained the first large quantity of drugs washed up on Galveston beaches in at least a decade Heyse said.

No one knows how or where the drugs got in the water, but typically they are thrown overboard when law enforcement attempts to board a smuggler's vessel, he said.

Occasionally drugs wash ashore and the police keep quiet about it in hopes of finding the owner, Heyse said. “Unfortunately there was nothing in the bag that would lead them anywhere,” he said.

Although the amount found was large, it amounts to a fraction of the cocaine brought into the United States, Heyse said. Heyse recalled an entire ship loaded with cocaine being seized several years ago.

Dealers typically dilute the cocaine with baby formula or some other odorless, flavorless material, he said.

The 37 pounds would probably have been turned into 100 pounds of street product, Heyse said, or processed into highly addictive crack cocaine in home laboratories.

harvey.rice@chron.com