Sen. Joseph Lieberman, the Democratic candidate for vice president, visited the home state of Texas Gov. George W. Bush yesterday to hammer on Bush’s environmental record, accusing him of endangering the health of Texans by failing to stand up to industrial polluters. Speaking in a poor neighborhood near a petrochemical plant, Lieberman said federal data show that Texas leads the country in toxic emissions into the air and that Houston is the nation’s smoggiest city. In a debate with Al Gore on Wednesday night, Bush claimed to have signed legislation to require emissions reductions at older plants, but the facilities covered by that electricity deregulation law account for only a small portion of the state’s pollution and older plants in other industries remain unaffected. Bush has instead promoted voluntary emissions reductions for the other plants, but even the state says the voluntary program has had no measurable effect on emissions. The Gore-Lieberman campaign began running ads in Florida attacking Bush’s environmental record; the Democratic National Committee is running similar ads in other battleground states.