The Environmental Protection Agency has issued warnings to seven Phoenix-area sand and gravel firms that they need to control dust or they could be barred from bidding on federal road projects or even face fines.
The EPA sent violation notices to each company in July after conducting several inspections at sand and gravel plants. Some operate along the Salt River where some of the highest dust pollution readings are recorded.
Dust is a key target for pollution-reduction efforts because research shows repeated exposure can lead to infections and chronic lung problems and may be especially harmful to the elderly and children.
Local officials fear that road building could come to a screeching halt if federal funds are pulled.