The Immigration Reform and Control Act, also known as the IRCA (I-R-C-A), is the primary federal law that addresses the rights of immigrant workers. Under the Act, employers must treat immigrant workers who are legally authorized to work in the United States in the same manner as natural-born or naturalized American workers. This primarily means that employers must avoid engaging in any discriminatory employment practices such as hiring and terminating immigrant workers based on their nationality or citizenship status. Employers are also expected to ask all newly hired employees for proof of employment eligibility. Employers should note that immigrant workers don't all carry the same employment eligibility documents, such as green cards. As a result, immigrant workers should be allowed to present any document or combination of documents to show employment eligibility, as long as the documents are allowed by law. Employers shouldn't prefer one document over others or refuse to accept proper documents. IRCA provides for a fine of $100 (one hundred) to $1000 (one thousand dollars) for each instance of document abuse by employers. Employers who violate any other of the IRCA provisions, such as hiring an illegal alien or threatening immigrant workers during an IRCA investigation, will be subject to severe penalties as well.