N.H. Rev. Stat. Ann. § 140:8

This chapter shall not be construed as repealing any laws of the state relating to chemical or physical agents or exposures to them but shall be held and construed as auxiliary and supplementary to them, except to the extent that they are in direct conflict with this chapter, in which case this chapter shall be controlling. Nothing in this chapter shall preclude the right of any governing body of a municipality to adopt ordinances or rules not inconsistent with this chapter.