SAN DIEGO (AP) — A college student who was forgotten by federal drug agents and left in a holding cell for five days without food, water or access to a toilet says that he drank his own urine to survive.

Daniel Chong also said that he bit into his glasses to break them and tried to use a shard to scratch “Sorry Mom” into his arm, according to a story published Tuesday in U-T San Diego (http://bit.ly/JRlSr8 ).

The 24-year-old engineering student at University of California, San Diego, was swept up as one of nine suspects in an April 21 drug raid that netted 18,000 ecstasy pills, other drugs and weapons.

Chong said federal Drug Enforcement Administration agents told him he would be released. One agent even promised to drive him home from the DEA field office in Kearny Mesa, he said.

Instead, he was returned to a holding cell to await release. DEA spokeswoman Amy Roderick said he was accidentally left there.

Chong said he could hear the muffled voices of agents outside his five-by-10-foot windowless cell and the sound of the door of the next cell being opened and closed. He kicked and screamed as loud as he could, but apparently, his cries for help went unheard.

“I had to recycle my own urine,” he said. “I had to do what I had to do to survive.”

When he was found on April 25, he was taken to a hospital and treated for cramps, dehydration and a perforated lung — the result of ingesting the broken glass.

“When they opened the door, one of them said ‘Here’s the water you’ve been asking for,'” Chong said. “But I was pretty out of it at the time.”

Chong also ingested a white powder DEA agents said was left in the cell accidentally and later identified as methamphetamine. He described having hallucinations, saying: “I was completely insane.”

The agency hasn’t commented on Chong’s claim that he was without basic necessities for days. He also said the lights went off at one point and stayed off for several days.

Chong’s attorney, Eugene Iredale, said he plans to file a claim against the federal government, and if it is denied, he will proceed with filing a federal lawsuit.