more chance of showers and isolated thunder. >> okay. crazy weather. >> bye. tonight high alert. a harrowing security scare in washington. fears of a gunman on the loose at the navy yard where so many were slaughtered just two years ago. tonight, the massive response and the terror warnings before july 4th. toxic emergency. thousands of people evacuated from their homes in the middle of the night as a train disaster sends a cloud of poisonous chemicals in the air. >> trouble in the water before a big holiday weekend. growing concerns over so many shark attacks in the east as a popular vacation spot vanishes before our eyes in the west. and sparks fly as nascar asks fans to leave the confederate flag at home. "nightly news" begins right now. ♪

this is "nbc nightly news with lester holt" reporting tonight from los angeles. good evening. amid warnings about isis and the threat of attacks over the july 4th weekend, the images we saw plastered across the tv screens from washington this morning were exactly the kind we feared most. ambulances and police cars racing to reports about a shooter on the rampage. of course, by now we all know what happened at the navy yard this morning was a false alarm, but the sheer size of the police response not only at the navy yard, but across the capital spoke volumes about the disturbing and very real security climate we all find ourselves in this holiday weekend. we start tonight with peter alexander and a nation on edge. [ sirens ] >> reporter: this morning, fears of another mass shooting sparked a city on edge. the 911 call came just after 7:00 a.m.

a woman inside a washington navy yard building reported hearing possible gunshots. workers scrambled for cover. >> i heard someone yelling get out of the building. stay away from the cafeteria. get out of here and everyone started running toward the exits. >> reporter: police swarmed the scene. helicopters circling overhead. >> west and northeast corner. it's clear. >> reporter: the lockdown lasted hours and the drama playing out on live tv. >> reports are telling us that there is an active shooter. >> reporter: s.w.a.t. teams searched the navy yard just a mile from the capitol one building at a time before giving the all-clear. >> there was no criminal act and no shots fired and no one was hurt. >> a huge relief after a lone gunman roamed the hallways here, killing 12 people. d.c.'s police chief stressed today's caller did exactly what she should have done, that it wasn't a malicious hoax. >> we take every event here in washington very serious, and our posture remains high. >> across the country law enforcement agencies are on alert, with isis urging attacks over the fourth of july holiday and the

muslim holy month of ramadan which this year coincide. law enforcement and military personnel, top targets. the concern even reaching overseas. the air force's 48 fighter wing canceling fourth of july events at a base in england, citing threat assessments. new york city, with one of its largest police presences ever for independence day and boston and l.a. beefing up patrols, focusing on lone wolf attacks. and a specific warning to be on the lookout for bulk purchases of fireworks that could be used as explosives. here in the nation's capital, thousands of tourists are already arriving. >> mom's got it all laid out. we're doing the metro. we can walk to our hotel so our planning is our safety measure. >> reporter: the holiday jitters are getting so much attention now that one purported isis supporter today tweeted, quote, americans are terrified of july 4th. that's not the response that u.s. officials are looking for. they want people to be on the lookout and

enjoy. >> thanks. another big story we're following, a toxic air emergency in tennessee after a train carrying poisonous chemicals flew off the tracks in the middle of the night. thousands of homeowners awakened and evacuated over fears of their safety. we get the latest on this from nbc's janet shamlian in maryville, tennessee. >> reporter: without warning, a train carrying poisonous materials derailed and caught fire near knoxville, forcing more than 5,000 people to evacuate their homes in the middle of the night. >> by 2:00, 2:30 it smelled bad. >> i grabbed what i could and got out as fast as i could. >> my thought was the air poisonous? i was worried that breathing was going to be an issue. >> 52 people went to the hospital. at least 25 were admitted after being exposed to the toxic chemicals. rail line company csx says there were no injuries, but nbc news has learned the area is so toxic crews are being told to use extreme caution. >> we're in the process of controlling the fire

and containing the fire. >> reporter: this afternoon the thick plume of smoke billowing from the train was still visible miles away. >> i was kind of confused. i didn't know what was going on. >> my heart was beating out of my chest. >> reporter: officials say the freight train was traveling from ohio to georgia when a tanker went off the track around midnight. 27 of the 57 cars were carrying dangerous substances including 24,000 gallons of a toxic and flammable chemical used to manufacture plastic. if inhaled at high levels it can cause headaches, nausea and kidney irritation. a two-mile evacuation zone was quickly put into place. >> when you've got an official, fireman or policeman coming to the door telling you you've got to go, it's time to go. businesses were forced to close and residents were told not to drink the water. tonight many remain at red cross shelters waiting for the all-clear to return home. >> reporter: and the epa is on the scene right now. they're taking samples of the air while the fire is largely out at this hour, no one is

going home tonight. authorities will re-analyze and make a decision on that in the morning. lester, back to you. >> janet, thank you. tonight, five years after one of the worst environmental disasters this country has ever seen bp has agreed to pay a record $18.7 billion to the federal government and five states so badly damaged by the deepwater horizon oil spill. you'll recall it poured millions of gallons of oil into the gulf for 87 days. even years later, a lot of places there are still struggling to come back and people there are saying tonight this settlement isn't going to cut it. we get details from nbc's kerry sanders in plaquemines parish, louisiana. >> reporter: five years after an explosion killed 11 men and americans watched millions of gallons of oil gush into the gulf of mexico bp and five coastal states announced an historic agreement. this morning at simultaneous news conferences, state officials called it a major achievement. >> today's settlement is a game

changer for louisiana, its communities and its families. >> reporter: bp will pay $18.7 billion to the federal government and the five gulf coast states for economic and environmental losses as well as penalties for federal clean water act violations. the payout is 54% more than bp's profits last year and will be distributed over the next 18 years. that's nearly $215 million for each of the 87 days oil gushed into the gulf of mexico. this agreement settles claims with 400 local communities, but in especially hard hit plaquemines parish in louisiana local politicians say the deal is not enough. >> what we're doing is making sure that the future generations in plaquemines parish are being justly compensated. >> reporter: at p & j oyster company in new orleans, a 139-year-old institution, today only enough oysters for two shuckers on the line. this is what it looked like before the impact of

the oil spill. >> who would have thought five years ago we wouldn't have oysters enough to sell to provide to the customers that we had? you know, who would have thought that the public oyster grounds east of the mississippi river would be non-productive to this day? >> reporter: bp officials said today that this agreement will pay a significant amount of money for the restoration of natural resources. this agreement, this settlement is in addition to the estimated $10 billion settlement being paid to individuals for their losses like the oystermen that own these boats over my shoulder here. lester? >> kerry sanders, thank you. there is new fallout over the fiery debate over the confederate flag. nascar after making it clear last week that the flag has no official place at its events is now going even further with a request many of its fans may not like ahead of one of the biggest racing weekends of the year. nbc's kevin tibbles explains. >> reporter: it is

brash and fast and fans of nascar have never been shy about showing their patriotism or southern roots, but while flags fly in the infield, one is no longer welcome. the confederate flag. in a statement today, nascar asked fans to refrain from flying it, saying we are committed to providing a welcoming atmosphere free of offensive symbols. in a show of support, 32 speedways hosting nascar events signed the announcement. >> they're creating an environment where more fans and especially african-american fans in this instance can feel welcome. >> reporter: reaction on twitter was passionate on both sides. shout out to nascar for turning their backs on their fan base in favor of political correctness said one. bravo, nascar asking fans to leave their confederate flag at home. it's a repressive symbol and not welcome, said another. earlier, number 88 dale earnhardt jr., stated he supports nascar's stand.

>> it's offensive to an entire race and does nothing for anybody to be there flying. it belongs in history books and that's about it. >> reporter: the flag ban will not be in effect at the daytona international speedway for this sunday's race to allow fans time, but nascar is offering a free stars and stripes to those who want to trade in their stars and bars. kevin tibbles, nbc news, chicago. there is mixed news to report today on the economy. while new numbers show that employers added a healthy 223,000 jobs last month and the unemployment rate dropped to 5.3% economists say wages didn't increase at all, and more people gave up looking for work reflecting some discouragement for many in the job market. turning now to politics and the newest candidate to join the democratic race for president. former virginia senator jim webb entering a field that includes hillary clinton and vermont senator bernie sanders who raised a reported

$15 million since announcing his campaign in april. last night he drew a crowd of nearly 10,000 for a rally in madison, wisconsin. in the gop race, the serta mattress company is the latest to cut ties with donald trump. by some estimates trump has lost over $50 million in deals over controversial comments he made about immigrants from mexico. tonight, there are no plans to close down beaches along the north carolina coastline this holiday weekend despite a recent rash of shark attacks. safety officials are scrambling to find a pattern of the attacks while some businesses say they're already noticing a drop in tourists. nbc's gabe gutierrez has more from the outer banks. >> reporter: the rescue was frantic. >> first responders respond to lifeguard beach. we have a subject that has an injury from possible shark. >> reporter: 67-year-old andrew costelo now in good condition after a shark bit him on his leg, hip and both hands. >> you could see a

pretty decent size, about baseball-size gash taken out of his knee. >> reporter: it was north carolina's seventh shark attack in three weeks a record. >> i am reviewing with the public safety personnel to make sure that we have the personnel in place to respond to any potential emergency. >> reporter: but this holiday weekend officials have decided not to close any beaches. >> we have no indication that we need to do that and we want to make sure people are aware when they go into the water that there are risks there. >> water temperatures are warm, warmer than normal at this time of year which means summer arrived sooner and with it came the sharks that move from the south as well as many of the things that they eat. >> reporter: so far this year there have been 25 unprovoked shark attacks in the u.s. 11 of them in florida, seven in north carolina, four in south carolina. patrick thornton is among the survivors. >> i could see the fin slowly coming by me. a shark is upon me. it's attacking me. this could be it. >> reporter: this is an up-close

view of divers in florida when tiger sharks got curious. at this north carolina coffee shop all the unwanted attention has already taken a bite out of their business. >> this is our livelihood. the couple of months that we have during the season is what sustains us through the winter. >> reporter: tonight, north carolina is hoping the sharks stay away, but the tourists don't. so far there have been 25 shark attacks throughout the u.s. this year compared to 52 all of last year, but here in north carolina, emergency crews will remain on high alert throughout the weekend. lester? >> all right, gabe. thanks. still ahead tonight, we have sharks on one coast, drought on the other. a once hugely popular july 4th spot nearly run dry. now the summer may never be the same here in the west where record drought is ruping much more than holiday fun. also kids who grew up watching her now watch with kids of their own, but after 44 years a beloved face from sesame street is moving out of the neighborhood.

we're back atop the nbc news bureau in los angeles where the hottest days of the year are arriving with no relief from the blistering drought here. californians cut their water use by a record 29% in may. that's, of course, vitally important, but there's no conserving your way out of a drought like this. meantime, it has severely altered the california lifestyle in so many ways, ways that will be especially apparent as people head off for outdoor adventures this holiday weekend.

we get more from nbc's jacob rascon. >> reporter: the san antonio reservoir used to be one of california's largest in a popular independence day getaway, but after four years of extreme drought there is almost nothing usable left. >> it's near what they call dead pool which means you can't release any more water out of it. >> reporter: and for the first time ever, the lake is now closed indefinitely. >> they're used to coming to having the lake, to picnic, to swim, boat, to fish and it's gone. >> my family is sick about it because it's in my backyard. it's a sad thing. >> reporter: up and down the coast, californians are changing the way they live. >> the kids can't run around the sprinklers like we grew up. we can't wash our cars. >> reporter: lush lawn like the reservoirs are vanishing. the community of mountainhouse recently came within one day of running dry before buying expensive water on the open market. another community, east porterville relies on donated

water bottles and tanks after hundreds of its wells simply dried up. the fixes are only temporary. >> a lot of people are very concerned about what could happen if we get another dry winter. >> you won't be the only community? >> no, this will be a statewide, epic crisis. >> reporter: another major reservoir, folsom lake, the primary water source for hundreds of thousands of northern californians is losing 1.4 billion gallops every day, an entire region facing a new reality, buying time desperate for lasting relief. >> reporter: another fourth of july tradition is also suffering because of the drought. all personal fireworks are banned in dozens of community across the west including here in california. lester, an increasing number of cities have canceled their fireworks shows saying it is simply not worth the fire risk. >> i can only imagine what an anxious weekend this will be for firefighters. >> one of the more anxious weekends. firefighters have been preparing for this weekend for months. >> jacob rascon, good to see you. thanks.

in a moment, we're back with a heartbreaking self-defeat. if you have to lose, you don't want to lose like this.

we're back inside now. with stunning new details about an air disaster that happened overseas back in february. we should warn you, the video is disturbing. officials say the captain of a transasia airlines plane mistakenly turned off its only working engine clipping a highway before slamming into a river. the pilot is heard on the cockpit voice recorder saying wow, pulled back the wrong side throttle seconds before impact. not realizing his mistake until it was too late. 43 people were killed in that crash and amazingly, there were more than a dozen survivors. new york's newest millionaire is one of the brave first responders from 9/11. carmelo mercado won $5 million and forced to retire

in 2004 with a lung condition he developed at ground zero. a lot of people aren't going to like the sound of this or lack of sound because the maker of bubble wrap is unveiling a new design that will no longer make that satisfying pop when you burst the bubbles. the old version will still be available, but shippers may decide to go with the new one because it's designed to take up less space in warehouses, and a bit quieter, too. a heartbreaking finish at the women's world cup in canada, japan taking on england in the semifinals. it was all tied up in the final minute of the match when a ball off the foot of england defender laura bassett bounced off the crossbar and landed in her own team's goal, giving japan the go-ahead score and the victory and they'll take on the u.s. in the championship game on sunday. your heart has to go out to her. up next after more than four decades, "sesame street" is about to lose one of its friendly neighbors.

a gunman killed a woman visiting the tourist hot spot. next at 6: her father talks about the moment they heard the gunshot. ===janelle/take vo=== plus: a south bay community considers a high-tech way to fight crime, why critics say it goes too far. finally tonight, after a remarkable 44 years with big bird, grover and oscar the grouch, the actress who plays the beloved maria is moving away from "sesame street." so many of us either grew up watching her or watched along while our kids did, and now the

neighborhood just won't be the same without her. here's rehema ellis. >> my name is maria. >> millions of us have grown up watching her. for 44 years, maria has been the darling on public television's most beloved show "sesame street." ♪ sunny day ♪ ♪ sweeping the clouds away ♪ >> reporter: now sonia manzan who has played a wife, mother and fix-it shop owner is retiring from the show that joined her with adorable characters including oscar the grouch. >> i'll give you something nice that you really like. i got it just for you. >> what is it, oscar? a pie in the face or something like that? >> reporter: she got to "sesame street" when she was only 21. a drama student at carnegie mellon university, a first-generation puerto rican-american from the bronx. >> what is the spanish word for amazing? >> estupendo! >> manzano was one of the first hispanics to appear on national

television, a cast member and much more winning an impressive 15 emmy awards for writing. >> the challenge is taking a very complex issue and making it very simple, something that a 4-year-old can understand. >> reporter: in many ways, playing maria mirrored her life. the character maria got married the same time sonia did. today manzano's sesame street fans were buzzing about her retirement tweeting heart you, sonia. the first latina i saw on tv in the '70s. i have always enjoyed the maria moments with oscar the grouch. was she a role model to you? >> i always thought she was a positive influence. >> she's like part of the family. >> she'll be missed. >> she will. ♪ who are the people in your neighborhood ♪ >> a television legend who charmed children and adults in all of our neighborhoods. rehema ellis, nbc news, new york. and that will do it for us on a thursday night. i'm lester holt reporting from los angeles.

i hope you have a wonderful and safe holiday weekend. for all of us at nbc news, thank you for watching and good night. what appears to be a random act of violence. new details tonight on a a young woman's life taken in what appears to be a random act of violence. new details tonight on a stunning shooting along one of the busiest tour hot spots in san francisco. thanks for joining us. i'm janel wang. >> i'm jessica aguirre. she was walking along the embarcadero when suddenly she was shot. they tried desperately to save her life. they couldn't. she died at the hospital. tonight the man acushion ochd

killing -- accused of killing her is in jail. we begin with cheryl hurd live in pleasanton. it is senseless and unmanageable loss for that family. >> it is. it is a heartbreaking story. i spoke with her parents a couple hours ago, and they are right now meeting with their minister. they say they have a strong faith and it's that that's getting them through. >> she was a beautiful human being. >> we loved her so so much. and we were such a close family. >> reporter: and that closeness is getting liz sullivan and her husband jim steinly through the random shooting death of their daughter kate. >> starting to be in her prime. had so much to live for. to die so senselessly is terrible. >> reporter: last night kate steinly was having lunch with her father and a friend. they had a good day. they were winding up they were evening walking