What protections are there for "whistleblowers"?

Bibliographic Details
Corporate Author:	United States. Employment Standards Administration. Wage and Hour Division
Format:	Government Document Book
Language:	English
Published:	Washington, DC : U.S. Dept. of Labor, Employment Standards Administration, Wage and Hour Division, 2008.
Series:	Fact sheet ; #62R
Subjects:	Foreign workers > Legal status, laws, etc. > United States.
Online Access:	https://purl.fdlp.gov/GPO/LPS101728

Description
Item Description:	Title from title screen (viewed on Sept. 9, 2008). "January 2008." Electronic resource.
Physical Description:	1 unnumbered page : digital, PDF file.
Format:	Mode of access: Internet at the U.S. Dept. of Labor web site. Address as of 9/9/08: http://www.dol.gov/esa/whd/regs/compliance/FactSheet62/whdfs62R.pdf ; current access available via PURL.