CLEVELAND, Ohio -- Friday's racing program at Thistledown is in jeopardy after jockeys, citing safety issues, refused to ride Wednesday, forcing management to cancel the eight-race program. "We don't mess around when it comes to safety," said retired Thistledown riding champion Junior Rivera, who represents riders as a regional manager for the Jockeys' Guild.          According to Thistledown publicist Sherry Pinson, the only communication issued by Thistledown management was on its Twitter account. It read, "Today's card has been canceled due to circumstances beyond our control. All wagers refundable. Please join us Friday at 1:40 p.m." Thursday is a dark day at Thistledown. Terry Houghton, one of Thistledown's leading riders is hopeful the situation can be resolved. "I spoke with (director of racing) Dave Ellsworth tonight (Wednesday) and I think we might have the bases covered. Everybody wants to get back to work, but we'll have another meeting Thursday." Houghton said he and the other riders are asking management to make sure there are adequate safety policies in place, not only during live racing, but also during morning training hours. "We need two outriders (lifeguards on horseback) and a paramedic and an EMT (emergency medical technician) that know racing emergency procedure to assure our safety out there," he said. Houghton said an accident involving two horses during Wednesday morning training hours brought the situation to a head. "It was a big mess," he said. "One exercise rider was hurt and the response time was poor. There was only one outrider and she couldn't be expected to catch two horses at the same time."