At a craft brewers’ convention in Denver this week, Bob Pease, the chief operating officer for the Brewers Association, said during a news conference that Ms. Collins’s office had reached out to the industry group as it was busy fighting the spent grain rule. He pointed out that Ms. Collins’s statement to Dr. Hamburg at the Senate hearing echoed language that the association had been using.

On Tuesday, a bill that would exempt brewers from the grain sale regulation was introduced in the House by three members from the brewery-heavy states Colorado, Vermont and Maine and Representative Steve Womack, Republican of Arkansas, which has a relative handful of breweries.

In introducing the legislation, they used familiar language:

“The F.D.A.’s proposed rule is a solution in search of a problem.” It is a phrase the Brewers Association has repeatedly used.

Mr. Udall, in a letter to Dr. Hamburg and the F.D.A., urged the agency to reconsider the rule. In a separate letter, Ms. Collins and Senator Angus King, an independent from Maine, told Dr. Hamburg that it would result in wasted grain and more expensive animal feed for farmers. The cost to farmers and brewers is unclear.

Under the Food Safety Modernization Act, which President Obama signed in 2011, the makers of food for livestock and pets would have to write food-safety plans aimed at identifying hazards and preventing contamination. The brewers’ sale of spent grain as animal feed would subject them to the same regulations.

At a cost of about $50 per ton, the sale of spent brewers’ grain is worth about $160 million a year in the United States, according to Tom Wilkinson, who directs sales of that grain for the Commodity Specialists Company. Most of the grain is sold by the biggest brewers, Anheuser-Busch InBev and MillerCoors. The Beer Institute, which represents the industry’s largest players, says complying with the new rules could initially cost a big brewery $13 million, with other costs to follow.

Most of the smaller companies that the Brewers Association represents are most likely to be exempt from some of proposed requirements; the sale of spent grain does not make up enough of their revenue. Eighty-nine percent of the brewers represented by the association donate their spent grain, so under the new regulations, they would simply have to make sure it is stored in containers that are safe for food storage. But the rule would be more onerous for the larger brewers that the association represents, like Boston Beer Company.