The Cecil Smith landfill in Dartmouth is one step closer to being capped and not cleaned. According to published reports , the state's Department of Environmental Protection has ruled it will allow Brockton-based Boston Environmental Corp. access to wetlands near the landfill as long as the company agrees to perform restoration measures. The DEP's ruling effectively overturns an August decision by the Dartmouth Conservation Commission, which denied Boston Environmental's application on the grounds that it did not provide enough information about how wetlands would be affected by the company's plan to cap the landfill with 2 million tons of contaminated soil. The DEP approval represents one of four needed for the state to move ahead on Boston Environmental's $18 million proposal.