As IT buyers focus on finding the most energy-efficient and coolest-running data-center systems, another environmentally friendly trend is taking off in the industry: the requirement to build hardware free of toxic substances.

The trend is the result of a European Union directive called RoHS (pronounced Roh-Hass or Ross) that requires any electronic equipment sold in the EU after July 1 be free of lead, cadmium, mercury and other toxins. While there is no similar legislation on the federal level in the United States, the regulation is having a ripple effect in the United States because vendors typically have a standard manufacturing process regardless of where a product is sold.

That means hardware vendors, including Dell, HP, IBM and Sun, are in the process of transitioning their global product lines to be RoHS compliant.

Experts say the regulation should be good news for users, who will find it easier to dispose of equipment that doesn't contain hazardous substances.

At the same time, issues could arise as the migration happens, analysts say. Products could be delayed if there are problems finding RoHS-compliant components. In addition, there may be questions about whether older equipment that is not compliant with RoHS will continue to be serviced even though the EU directive allows for hardware manufactured before July 1 to be serviced with non-RoHS-compliant parts.

"What enterprise buyers need to do is make sure they are educated and ask the right questions to find out the [RoHS] migration plans from wherever they are buying," says Eric Karofsky, a senior analyst at AMR Research.

Buyers should purchase from established vendors that can be relied on for long-term service commitments. "And ask them about future serviceability," he says.

Another concern is that RoHS-compliant products may have to be recertified as they are brought into enterprise environments.

Vendors, meanwhile, say they have been working on meeting these regulations since they were announced in 2003, and have validated and audited RoHS-compliant products along the way.