Large commercial and industrial users are required to comply with local hazardous waste guidelines. This would apply to the facility and property managers of commercial office buildings, hospitals, warehouses, manufacturing plants and retail stores—anyone who generates more than 100kg of hazardous waste per month (approx. 360 4' T12 lamps). Even under these circumstances, certain low mercury lamps are exempt—those that pass the EPA Toxicity Characteristic Leaching Procedure (TCLP) Test. You can access the EPA regulations at the website referenced above.
However, there are benefits to recycling, even when not required to do so. Keeping mercury out of the waste stream protects our groundwater. According to Earth 911, mercury doesn't breakdown and go away, it only alters its form and once in waterways is transformed by bacteria into the more toxic methyl mercury. Environmental stewardship demands that we take responsibility for the waste we generate, every little bit of it.