The White House has threatened to veto House Republican legislation aimed at preventing the Environmental Protection Agency from tightening farm dust regulations, arguing that the bill in unnecessary and could be used to weaken public health standards.

“As drafted, this bill would create serious problems for implementing Clean Air Act (CAA) public health protections that have been in place for years while adding uncertainty for businesses and States,” the White House said in a formal “statement of administration policy.”

“The bill therefore, goes far beyond its stated intent of prohibiting the Environmental Protection Agency (EPA) from tightening national standards for coarse particles, which the Administration has repeatedly explained that it has no intention of doing.”

EPA hasinsisted for months that it will not make existing regulations governing coarse particulate matter from industrial and agricultural operations — often called farm dust — more stringent.

But Republicans and some farm-state Democrats have nonetheless raised concerns that EPA will tighten the standards, alleging the move would impose a major economic burden on the agriculture sector.

The House Energy and Commerce Committee approved the bill, sponsored by Rep. Kristi Noem (R-SD), last month amid opposition from Democrats.

The White House said that in addition to being unnecessary, the bill would “create high levels of regulatory uncertainty regarding emission control requirements that have been in place for years.”

“Specifically, the bill's exclusion from the entire CAA of a new class of air pollutants called 'nuisance dust' (an imprecise and scientifically-undefined term) could be used to roll back existing public health protection limiting pollution from mining operations, industrial activities and possibly other sources,” the White House said.

The bill faces major hurdles to passage in the Senate.

The announcement was posted on The Hill Web site at http://thehill.com.