1:06pm: GOP presidential contender Herman Cain plans to hold a news conference in Phoenix later today to "set the record straight" about allegations of sexual harassment. Cain steadfastly denies that he ever harassed anyone. On Monday, Sharon Bialek became the fourth woman to accuse Cain of harassment, saying he made an inappropriate sexual advance toward her in 1997 while the two were in a car. At the time, she was out of work and seeking his help in finding a job. So what constitutes sexual harassment and how are these cases generally handled? We hear from an employment lawyer, who handles cases of sexual harassment. 1:12pm: While Cain denies all allegations of sexual harassment, he has also mentioned his sense of humor when addressing questions about the recent claims. Last week, Cain told the Wall Street Journal, "I do have a sense of humor, and some people have a problem with that." Cain has also said he does not make inappropriate comments to employees, but when is taking a joke too far? Katrina Campbell of Global Compliance works with companies to prevent sexual harassment in the workplace. She says that people often get in trouble for making jokes that aren't appropriate in the workplace. Campbell says while some people accused of sexual harassment are making a power player, others are just oblivious to the impact of their actions. 1:25pm: Half of the airborne mercury pollution in the US comes from coal-fired power plants. After years of study and debate, the Environmental Protection Agency is planning to announce new limits on mercury from coal plants in November. Meanwhile, utilities are scrambling to meet other new federal regulations and industry groups are asking the government to slow down. This is the second of a four-part series, Coal at the Crossroads. You can hear it all week on Here and Now.