The League of Conservation Voters and Defenders of Wildlife Action Committee launched a new round of television advertising in New Mexico against Republican Senate nominee Heather Wilson.

The former Congresswoman, who is running for the open Senate seat against Rep. Martin Heinrich (D), has been the target of a coalition effort from several environmental and conservation groups in recent weeks. The two groups responsible for the latest ad have already spent $700,000 in independent expenditures on the race this month, according to Federal Election Commission records.

American Crossroads, a Republican-aligned super PAC, also spent about $250,000 in the state this month on Wilson’s behalf.

The new ad, on which the environmental groups spent $150,000, accuses Wilson of voting to protect MTBE producers and oil companies from lawsuits regarding contaminating drinking water.

Roll Call rates the race as a Tossup.