What is the liability for contractors and lead dust poisoning? I heard theres a new law in 2010 for this?

The law you are referring to is 40 CFR 745 (LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES ) .   Beginning April 22, 2010, you may be affected by these regulations if you perform renovations on target dwellings as defined under the regs.  Per the regulations, "target housing" is any housing constructed before 1978 (exception:  housing for elderly persons or persons with disabilities unless a child resides in the dwelling).  Under this regulation, you may be required to take EPA-certified training as a renovator and must adhere to certain work standards that includes but are not limited to the following:

• Posting signs clearly demarking designated work areas;
• Preventing dust from immigrating beyond the work area;
• Placing plastic sheeting to protect floors and grounds;
• Ensuring all doors and windows within 20 feet are closed;
• Containing any waste and doing a thorough inspection after the renovation.

Check with a lawyer versed in environmental codes to learn how the upcoming law may apply to you, including training, certification as a renovator and inspector.