Sun Microsystems is co-operating with two government investigations following accusations that it allegedly discriminated against US workers when it laid off 3,900 staff last year.
The US Justice and Labor Departments are basing their investigations on the allegations of former Sun engineer Guy Santiglia, who claims that US workers were let go while foreign workers, with the controversial H-1B visa, were kept on.
Sun has categorically denied any discrimination. A spokeswoman said in an email that "foreign national status was not a factor in the selection" when the layoffs were calculated.
Nonetheless the former worker said that the Department of Justice's civil rights division "has asked for the citizenship status of every Sun Microsystems employee before and after the layoffs".
Neither government department would comment on ongoing investigations. But a Sun spokeswoman wrote in an email: "Sun is co-operating closely with both departments and is responding in a timely manner to the departments' requests for documents pertaining to Mr Santiglia's complaints."
The H-1B visa programme has been controversial for years. Proponents say that it allows US companies to keep their technological edge by enabling them to hire overseas workers with the latest skills on a six-year temporary basis.
But opponents say that the companies like hiring foreign workers from countries such as China and India because they can pay them less. The H-1B visa also ties workers to the sponsoring companies.
When lay-offs ravaged Silicon Valley last year, hi-tech companies applied for more than 342,000 H-1B visas compared with almost 300,000 in 2000, according to US government data.
Santiglia claims that the four people laid off in his group of 26 support workers were all Americans, even though there were H-1B workers there as well.
He has also claimed that Sun has since applied for three H-1B visas for his old job title. Sun has denied this.
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