What right to post-employment testing for exposure to Benzene and heavy metals do I have?

Hi, I work in the hazardous waste industry. I was tested for pre-employment baseline in 2021 then I finished my year long contract. I was never offered post-employment testing to monitor any exposure. I am now three weeks into a new contract with the same employer who forgot to do my pre-season baseline this year. They are requesting I establish a new baseline that would disregard all exposure from my previous contract and the first few weeks of this contract.