ARLINGTON, Virginia (CNN) -- The Humane Society of the United States is partly responsible for the magnitude of the largest beef recall in the nation's history, Agriculture Secretary Ed Schafer said Thursday.
Agriculture Secretary Ed Schafer denies there is any food safety hazard with the recall.
The Agriculture Department Sunday ordered the recall of 143 million pounds of beef that came from a California processing plant.
Animals at the site were videotaped falling down and being hoisted by forklift to get them to slaughter.
The tape is thought to have been made in October. Watch what sparked the recall »
"For four months they sat on that information," Schafer said, referring to the video, which prompted the USDA to withdraw its inspectors and close the facility.
The Humane Society posted the video in late January and said it was part of the group's undercover investigation of conditions at the Westland/Hallmark Meat Packing Company of Chino, California.
Schafer, expressing concern Thursday the group failed to immediately tell his agency about the footage, said they "sat on four months of production that went out into the marketplace that's now being recalled."
Humane Society president Wayne Pacelle said any delay in releasing the video was caused by a request from a California district attorney's office that has since filed charges against two men who worked at the plant.
Pacelle said his group went to local authorities because "we have seen the USDA time and time again not take action."
But San Bernardino County District Attorney Michael Ramos was slow to respond and the Humane Society then decided to post the video to "goad" authorities into taking action, Pacelle said.
"Our food safety system should not have to depend on a non-government organization to unearth violations of the law," he said.
The newly appointed agriculture secretary, in a briefing with reporters after remarks at a farm conference, declined to list additional retail outlets that may have bought and distributed the recalled meat products, some of which went to public school systems across the country.
Federal regulations consider the information proprietary, but proposed changes are being reviewed.
Schafer denied there is a food safety hazard with the recall. He said "one cow that we know of went down just before moving into the gate, and we were supposed to be notified and were not."
Since 2004, the government has required that cattle be able to walk to slaughter after an inspection by a USDA veterinarian -- largely as a precaution against bovine spongiform encephalopathy, or mad cow disease.
If the animal goes down after a veterinarian's pre-death inspection, which consists of observing the animals "at rest and in motion," veterinarians must reinspect the animal before it can enter the food supply, according to a USDA spokesman.
A congressional panel on food safety plans hearings next month on the beef recall and will have questions about inspections and the level of voluntary compliance with rules on animal processing.
"Had they not been presented with the undercover video of Westland, this problem probably would not have been discovered or even investigated by USDA," said Rep. Rosa DeLauro, the Connecticut Democrat who leads the House Appropriations Subcommittee on Agriculture Administration.
As of Thursday afternoon, officials had located 15.2 million pounds of the 143 million pounds of recalled beef. Agriculture officials said another 20 million pounds has already been consumed.
The largest portion of the recalled beef -- 50.3 million pounds -- went to federal food and nutrition programs, according to updated numbers from Schafer in a Thursday afternoon phone call with reporters. E-mail to a friend