Fire hasnt threatened an entire city on this scale since the San Francisco earthquake 100 years ago. The fire has grown explosively since sunday. Fort mcmurray, alberta, a city of 88,000, has been evacuated. The price of oil rose worldwide because of the catastrophe in Canadas Oil Sands region. At least 90,000 people are refugees, hundreds of homes, whole neighborhoods, are gone. Ben tracy is there. Reporter parts of alberta are literally hell on earth. 49 fires are raging, at least seven burning out of control. Senior wildfire prevention manager chad morrison. Let me be clear air tankers are notin not going to stop thi. I can feel the heat here. This is insane. Reporter after the fire tore through the town of fort mcmurray, this is what it looked like, not only burned out, but bom theres nothing there. Theres nothing left. Theres so many homes gone. Reporter exhausted firefighters sprawled on the grass while a lone mountie surveyed the empty streets. Eric lavellee cant comprehend it. Its Something Like youd see out of the movies. The bank was on fire when we were driving in. The trailer park that there was is gone. The super 8 is gone. One of the gas stations is gone. Reporter the canadian government sent in reinforcements as huge plumes of smoke grew in the sk no place felt safe, not even this evacuation center. There were hundreds of people in this shelter last night, but then the wind changed direction, and the fire headed this way, and they had to evacuate this evacuation center. They piled on buses in the middle of the night and were once again forced to leave. Donna guillamot was evacuated for the second time. Its very stressful. You dont know whats bushed and whats not burned. When youan and now youre sitting here, and all you see is red flames. Its pretty scary. Reporter these fires really have brought the Oil Sands Industry here in alberta to a halt, and thats because the Oil Companies have to make sure their employees are safe. But, scott, you dont hear anybody talking about the loz of business. What you hear people talk about is that so far there has been no loss of life directly related to these fires. Pelley lightning and drought thought to be the causes. Ben tracy near the fire line for us tonight. Ben, thank you. Well, there were no fatalities or injuries in a massive fire in houston today. A warehouse filled with hazardous chemicals went up, setting off a series of explosions. It took firefighters several hours to bring it under control. Today, the nations Top Republicans turned their backs on the partys presumptive nominee. Both president s bush said they will skip the republican convention, and the speaker of the house withheld his divided. I think what a lot of republicans want to see is that we have a standard bearer that bears our standards. Reporter House Speaker paul ryan, the highest ranking g. O. P. Elected official and chair of this summers republican convention, said he could not endorse the presumptive nominee. Im just not ready to do that at this point. Im not there right now. And i hope to, though, and i want to, but i think what is required is that we unify this party. And i think the bulk of the burden on uniifying the party will have to come from our presumptive nominee. Reporter ryan has previously criticize trumps inflammatory rhetoric but said the primary process needed to play out. This party does not prey on peoples prejudices. We appeal to their highest ideals. Reporter trump today did try to reach out to hispanic voters, sending this photo and tweet to mark cenco de mayo. The best taco bowls are made in trump tower grill, he wrote. I love hispanics. Grows a growing list of Republican Party elders who are distancing themselveses from trump. Both living former g. O. P. President ed george h. W. Bush and his son, george bush, sailed they wont endorse trump or attend the partys convention. And the two previous republican nominees, mitt romney and john mccain, will boycott the convention as well. Trump has said he can win the election even if the party does not unify behind him. But ttha plenty of wellknown republicans are eager to fall in line. Theyre calling now, and theyre calling us all, and theyre saying, wed love to get on the train, the trump train, they call it, but wed love to get on the team. Reporter trump responded to ryan by saying he wasnt ready to endorse his legislative agenda, either, though he held out hope for compromise. Scott, all year, ryan has been developing proposals and bills to help distance rank and File House Republicans from trump. Mission accomplished. Pelley major garrett, thanks. Also skeptical of donald trump, our cbs news poll gives Hillary Clinton a 27point lead among women, and we have more from nancy cordes. Reporter if you google clinton, the first thing that pops up is a campaign ad offering an official hillary for america woman card for those who sign up on line, a play off this nowinfamous trump comment. Well, i think the only card she has is the womans card. Reporter clintons holding a good hand, leading trump among white women, for instance biker 11 point. The last democrat to win white women in a president ial election was her husband in 19 96. In 2012, they went for mitt romney by 14 point. Trump insists he can make up ground because he knows what women want. Women want strong military. They want to know that theyre secure in our nation. Women want Womens Health issues taken care of, and hillary is not going to do it like me. Reporter as she works to cement a sisoo taken to accusing trump of. Demeaning women. Demeaning women. Demeaning and degraigd things about women. Reporter she invoked gender politics again in a phone interview with the l. A. Times. When he questioned my qualifications to be president , i knew that the subtex was questioning womens qualifications in general. Reporter we learned this afternoon that some of clintons top aides, including reportedly her longtime confidant, huma abedin, have now been interviewed by the f. B. I. About clintons use of a private server. Clinton herself has not been interviewed yet, scott, but says she will cooperate if asked. Pelley nancy cordes, nance, thanks very much. There hasnt been much talk recently in the campaign about iraq but that may change after this week. A surprise attack killed a u. S. Navy seal tuesday in iraq. Petty officer first class Charles Keating responded to a call for help fromdi allies and american advisers who were being overrun by isis. Charlie dagata is in iraq tonight. Reporter only 20 minutes into the battle, u. S. Forces knew they were in trouble. They called for backup. gunfire then things only got worse. The navy seals rescue team found themselves pinned down in an intense firefight over 120 isis militants. Run reporter kurdish soldiers and their u. S. Advisers were forced to take cover. The attack seemed to come from nowhere. And petty officer first class Charles Keating iv was among those shot in the gun battle. Even the blackhawk helicoprs keating came under fire. Isis launched this surprise attack at around 7 30 near the village of it, el skuf. According to officials, the mill fants flooded in from the south piercing the front line with bulldozers. The americans fought for nearly two hours before finally getting away. U. S. Officials told us the area had been relatively quiet for a month and was considered low risk. It just shows how the front line against isis can change in a flash, scott, and how close u. S. Forces are to it. But u. S. Military officials here stress those navy seals only came forward to back up the americans and would not have joined the firefight otherwise. Pelley Charlie Dagata reporting from baghdad tonight. Charlie, thank you. Today, the federal government banned the sale of Electronic Cigarettes to anyone under the age of 18, and it imposed heavy multibilliondollar industry that has almost no oversight. Last year, three million teenagers used ecigarettes. Heres dr. Jon lapook. Reporter for years, ecigarette have been flying off the shelves, despite f. D. A. Concerns about their health effects. With todays ruling, the agency finally has the power to regulate them. Were finally leaving the world of the unregulated, wild, wild west when it comes to the sale of ecigarettes and cigars. Reporter mitt zoeller directors the f. D. A. Center for tobacco products. More teens use ecigarettes than regular cigarettes, and historically there was no regulation of these pruxes whatsoever. Reporter manufacturers of ecigarettes will be required to get their products approved by the f. D. A. And report any harmful ingred yents. I finally found a smarter alternative to cigarettes. Reporter these cigarettes contain nicotine but not cancercaw causing tar in regular cigarettes. Both f. D. A. And c. D. C. Have been concerned about other potentially in the vapor, as well as the effects of nicotine on the developing brains of adolescents. Nicotine is addictive, and no kid should be inhailing vape thoors contain nicotine into their lungs. Reporter from 2011 to 2015, ecigarette use increased from 1. 5 of High School Students to 16 . During that same period cigarette use dropped from 16 to 9 . Is there a sense on your part that perhaps in the future those kids using ecigarettes might start smoking . The jury is out on the gateway effects of ecigarettes, but we dont need the answer to the gateway question now to be able to conclude as a Public Health matter that kids shouldnt be using ecigarettes in the first place. Reporter manufacturers will have a grace period up to three years. After, that the f. D. A. Will begin enforcing regulations to prevent products from being sold. They dont meet requirements. Pelley dr. Jon lapook, thank you, could only be called a war crime. At least 28 people were killed, many women and children, in an air strike on a camp of defenseless refugees. It was in rebel territory near turkey. We dont know who fired the shot. These deaths add to the 320,000 who have been killed in five years of syrian civil war, but there is another cost, and that is the loss of irreplaceable history. The inheritance of all humanity. Inside syria, Elizabeth Palmer met the heroes in that fight. Reporter the music filled an ancient Roman Amphitheater that only three months ago was under isis control. It, like most of the ruins here, only survived that occupation by luck. But a trove of palmyras smaller treasures were saved by dedicated archaeologists, syrias very antiquities maamoun abdulkarim. His mission is to protect syrias heritage from all sides in the civil war. We met him among the empty display cases of the damascus archaeological museum. Its from the islamic period. Reporter right at the start of the fighting, he emptied and closed all of syrias antiquities museums. As for the priceless exhibits, some 300,000 objects, he and a very few trusted colleagues hid them. Will you tell me where . No, never. We are just small group. Look here. Reporter but he did agree to show us photos of the crates in their secret hiding place. Maamouns greatest triumph came in palmyra. His team managed to evacuate 99 of its Museum Artifacts to safety in damascus just as isis they destroyed several important buildings and laced the site with explosives which had to be carefully detonated. Syrias civil war has kept its treasures off limits for more than five years now. But abdulkarim is quietly planning for peace, eventually. And the day concerts in the amphitheater are not just for the benefit of soldiers but once again open to the world. Elizabeth palmer, cbs news, damascus. Pelley investigators are learning more about the Health Issues suffered by prince. And passengers had a terrifying flight when the cbs evening news continues. Pelley two weeks after his death, we are learning new details about the health of rock legend prince. Jamie yuccas reporter the headline of todays Minneapolis Star Tribune percocet found in princes system prompted the medical examiner to push back against such media reports saying in a Statement Released late this afternoon, her office has not released any information to anyone, including law enforcement. Law enforcement sources tell cbs news they are trying to determine the source of prescription pills found on prince and in his home. An attorney for howard kornfeld, a prominent drug Addiction Treatment doctor in northern california, sails the doctor was contacted to help prince the day before the singers death. Kornfeld sent his son, andrew, to minneapolis to facilitate treatment. William mauzy is kornfelds attorney. Andrews purpose in being there was to describe the recovery without walls program, to familiarize prince with that. Reporter instead, an driewfs among the group that found prince unconscious in the elevator the next morning. Andrew kornfeld had in his possession an drug called buprenorphine. Dr. Shiela specker is an addiction specialist at the university of minnesota. Buprenorphine is used particularly for withdrawal, so a person may be to to withdrew from opiods, or they may be to for maintenance. Reporter the medical examiners toxicology report determining princes cause of death could come next week, but, scott, it could also be sealed due to the ongoing criminal investigation. Pelley jamie yuccas near princes home tonight. Jaime, thank you very much. Extreme turbulence gave passengers a flight theyll never forget. Unless you have allergies. Flonase is the first and only nasal spray approved to relieve both itchy, watery eyes and congestion. 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Ask how enbrel can help relieve joint pain and help stop joint damage. Enbrel, the number one rheumatologistprescribed biologic. Pelley passengers on a jet had the the fright of their lives yesterday in extreme turbulence over indonesia. Vinita nair has this. Reporter on this cell phone video, you can hear passenge screaming as the airbus at30 violently shakes. The turbulence started 45 minutes before the flight was scheduled to land in jakarta. The shaking was so strong, that oxygen masks deployed, and storage begins started to rip. Photos posted on social media by passengers showed food and garbage strewn all over the cabin. Nenden nurhaini was on the flight. In my group, there are three injured people, she said. On the other group, some of them got injured on their legs and one of them got a severe head injury because of hitting the cabin ceiling. While the plane landed safely, more than 30 passengers and crew were injured, nine so seriously they were transport to the hospital. Many suffered broken bones. The airline is considered to have a good safety record. Scott, this flight was supposed to return since been canceled. Pelley ed vinita nair, thanks very much. When we come back, the hall of fame jockey and the brother who got him back in the saddle. If youve gone to extremes to escape your nasal allergies. Try clarispray. New, from the makers of claritin. With the 1 prescribed ingredient. And nothing is more effective at relieving your sneezing, runny nose and nasal congestion. Gaviscon is a proven heartburn remedy that gives you fastacting, longlasting relief. It immediately neutralizes acid and only gaviscon helps keep acid down for hours. For fastacting, longlasting relief, try doctorrecommended gaviscon. toilet flush if you need an opioid to manage your chronic pain, you may be sooo constipated it feels like everyone can go. Except you. Tried many things . Still struggling to find relief . You may have opioidinduced constipation, oic. Its different and may need a different approach. Opioids block pain signals, but can also block activity in the bowel. Which is why it can feel like your opioid pain med is slowing your insides to a crawl. Longing for a change . Have the conversation with your doctor about oic, and ask about prescription treatment options. Made on behalf of those living with chronic pain and struggling with oic. Pelley Kentucky Derby history could be made on saturday. A win for the 11 horse, exaggerator, would be the first for a trainer and jockey who were brothers. Turns out both have experience cracking the whip. David begnaud introduces us. Listen, were two sideave coin, okay. Were heads and tails. Reporter kent and keith desmormeaux grew up with horses, riding around the tiny cajun village of ic i guess he takes after his mother. I take after my father. Reporter why do you get the sense hes always opinion the one who kind of keeps you in line. You have good senses, yes. Exaggerator, an absolutely brilliant victory reporter kent is a superstar. Hes a hall of fame jockey who has been won the derby three times but hes always been a partier and drinker. The last five years he showed up inebriated before races. Few horsemen would hire him. It was this one who actually picked up the phone and said,boy, you need to tighten up. So when i got to the fork in the road, big brother was like, you need to go right because youre going wrong. Reporter kent is back in riding shape, and although still battling his demons, brother, keith, went to bat for him, convincing owners to give him another shot. There he is this saturday, kent will ride the derbys second favorite, exaggerator, trained by big brother did you think youd ever ride for him . No, no. Its totally surreal. I cant even believe it. I have to pinch myself. I cannot believe its my brother. Reporter you always looked up to him. Forever, still do. Dont say always. Say still do.