As a nationwide Salmonella outbreak linked to 550 million recalled eggs continues to unfold, key lawmakers are pressing federal regulators and the Iowa farms at the center of the recall for answers.

Rep. Rosa DeLauro (D-CT), who chairs the committee that controls the purse strings of both the Food and Drug Administration and Department of Agriculture, wants to know why federal regulators did not take action against DeCoster farms in light of nearly two decades of red flags.

DeLauro, a long time advocate for a strengthened federal food safety system, sent a letter yesterday to Agriculture Secretary Tom Vilsack and Dr. Margaret Hamburg, Commissioner of the Food and Drug Administration, to determine what the agencies knew about DeCoster farms, a group with a long history of violating health, safety, animal cruelty, and environmental laws.

“Workers were forced to handle manure and dead chickens with their bare hands and to live in filthy trailers, state environmental laws were violated repeatedly, and the company failed to disclose its investment in egg operations in another state to avoid a background check,” writes DeLauro in her letter to the agencies. “This pattern of regulatory non-compliance by the DeCoster operations should have served as a warning to regulators and warranted additional scrutiny of the company’s ability to comply with food safety standards.”

DeLauro also wants to know what the FDA knew about DeCoster’s compliance with the newly-implemented egg rule, what role egg graders from USDA’s Agricultural Marketing Service may have had at the plant, and whether any recalled eggs were sold into the federal nutrition programs like the National School Lunch Program.

The House Energy and Commerce Committee also launched an investigation into the recall yesterday, demanding more than five years of critical inspection records as well as all documents related to allegations of repeated violations of worker and animal health and safety laws, internal protocols from both Wright County Egg and Hillandale Farms. The Committee is asking for the documents by Sep. 7.

Wright County Egg recalled 380 million eggs on Aug. 13 and Hillandale Farm recalled 170 million eggs Aug. 19, making the total number of eggs pulled off the market 550 million. Hillandale said over the weekend it shared “a number of common suppliers” with Wright County Egg, including a company called Quality Egg, which provided feed and young birds.

Both Wright County Egg and Quality Egg are DeCoster companies.

FDA officials say the incidents are likely connected, but there is currently “no evidence that other farms are involved in this outbreak.” In a media briefing yesterday, officials said they hope to release more information and the inspection results from the ongoing investigation later this week.

The Egg Safety Center has provided a list of recalled egg products on its Website.

The letters from the Energy and Commerce Committee are available here.