Here are details as provided by CNA Insurance to the Safety & Risk Management Committee of PLANET and the recently enacted DOT hazardous material transportation regulations. 

All businesses that transport more the 17 ounces of a hazardous material should add a MCS90 endorsement to their insurance coverage.  Your insurance agent is familiar with this and can easily add the endorsement.

Additionally a recently added DOT regulation specifies that all businesses transporting 17 or more ounces of a hazardous material (such as gas, oil, propane or fertilizer to name a few) must prepare a hazardous Material Accident Action Plan and insure that all employees involved in transporting such material have that plan readily available in the vehicle and understand what action to take in the event of an accident where a hazardous material could spill or leak. 

The plan should be communicated verbally in all employee safety training sessions and a copy kept in all vehicles. Failure to provide a plan as described could result in a sizable fine. Liquid hazardous materials are also subject to container regulations that your company is (hopefully) already following

An example of when this plan could be effective is: An accident where the crew leader or job supervisor is injured or unconscious as a result of an vehicle accident and unable to respond to insure any hazardous materials being transported is not immediately made known to emergency personnel responding to the accident. Ask your insurance agent to further explain this. 

While this does not exclusively pertain to landscape service providers, it involves us because of our normal working situations. There are additional regulations that address vehicles crossing state lines that your insurance carrier could help you with.