R.I. Gen. Laws § 1-3-9: Continuance of existing uses.

No airport zoning regulations adopted under this chapter shall require the removal, lowering, or other change or alteration of any structure or tree not conforming to the regulations when adopted or amended, or otherwise interfere with the continuance of any nonconforming use, except as provided in §§ 1-3-14 — 1-3-16.