>>> BREAKING NEWS TONIGHT. THE SEVERE STORMS AND TORNADO WATCHES UP AND DOWN THE EAST COAST AS WE COME ON THE AIR. THE THREAT OF TORNADOES, HEAVY RAIN AND FLASH FLOODS. MORE THAN 80 MILLION AT RISK. MAJOR DISRUPTIONS TO AIR TRAVEL. MORE THAN 6,000 FLIGHTS CANCELED OR DELAYED. GROUND STOPS IN ATLANTA, BALTIMORE, PHILADELPHIA, WASHINGTON AND NEW YORK. IN D.C. FEDERAL OFFICES CLOSING EARLY. DANGER ON THE ROADS. A CHARTER BUS CRASHING IN PENNSYLVANIA. AT LEAST THREE KILLED. WE'RE TRACKING THE STORMS. >>> ALSO TONIGHT, THE DEADLY MID-AIR TRAGEDY. TWO FIREFIGHTING HELICOPTERS COLLIDING IN CALIFORNIA. WHAT WE'RE LEARNING. >>> DONALD TRUMP FIRING BACK AFTER FEDERAL PROSECUTORS ASK FOR A PROTECTIVE ORDER TO LIMIT WHAT HE CAN SHARE ABOUT THE 2020 ELECTION PROBE. WHY HIS ATTORNEYS SAY THE JUDGE SHOULD REJECT IT. >>> OUR NBC NEWS EXCLUSIVE ON THE CAMPAIGN TRAIL WITH RON DeSANTIS. AFTER YEARS OF AVOIDING QUESTIONS ABOUT IT, DeSANTIS NOW TAKING DIRECT AIM AT DONALD TRUMP'S FALSE CLAIMS ABOUT THE 2020 ELECTION. WHAT HE TOLD US. >>> THE ALLEGED PLOT TO ASSASSINATE UKRAINE'S PRESIDENT ZELENSKYY FOILED. THE WOMAN IN CUSTODY TONIGHT. >>> OUR NBC NEWS INVESTIGATION. THE POTENTIAL DEADLY FRENCH CONNECTION" AND "THE EXORCIST," THE LEGENDARY WILLIAM FRIEDKIN. >> Announcer: THIS IS NBC "NIGHTLY NEWS" WITH LESTER HOLT. >>> GOOD EVENING, EVERYONE, AND WELCOME. SEVERE WEATHER ON THE MARCH IN THE EAST TONIGHT, FORCING THOUSANDS OF FLIGHT DELAYS AND CANCELLATIONS. IN WASHINGTON, D.C. THE GOVERNMENT ALLOWED FEDERAL WORKERS TO GO HOME EARLY TODAY. D.C. UNDER A TORNADO WATCH UNTIL MID-EVENING. THE STORM PREDICTION CENTER WARNING OF A WIDESPREAD DAMAGING WIND EVENT THIS EVENING. THE LINE OF STORMS ON A TRACK FROM MISSISSIPPI TO MAINE. HEAVY RAIN, FLASH FLOODING AND LARGE HAIL IN THE FORECAST. AIRPORTS INCLUDING BALTIMORE, NEWARK AND PHILADELPHIA EXPERIENCING GROUND STOPS TONIGHT. ALL OF THIS BEING USHERED IN BY A COLD FRONT AS BLISTERING HEAT BRINGS CONTINUING TROUBLE ACROSS MUCH OF THE REST OF THE COUNTRY. VAUGHN HILLYARD IS IN WASHINGTON, WHERE FOLKS ARE BRACING FOR A REAL STORM THREAT. VAUGHN? >> Reporter: THAT'S RIGHT, LESTER. FOLKS HERE IN THE REGION HAVE NOT RECEIVED A STORM WARNING LIKE THIS IN MORE THAN A DECADE. A STORM WITH POTENTIAL DERECHO-LIKE IMPACT OF LIGHTNING AND GUSTY WINDS THAT'S NOW DESCENDING RIGHT HERE ON THE EAST COAST. TONIGHT THE SUMMER OF SEVERE WEATHER FROM COAST TO COAST IS RAGING ON. WILD WEATHER CLOSING IN, FORECAST TO BRING THE STRONGEST STORMS IN A DECADE INTO THE NATION'S CAPITAL INCLUDING DAMAGING WINDS, TORNADOES, HEAVY RAIN AND HAIL. FORCING GOVERNMENT BUILDINGS AROUND WASHINGTON, D.C. TO SHUT DOWN, SENDING ALL FEDERAL EMPLOYEES HOME THIS AFTERNOON. GROUND STOPS AT AIRPORTS ACROSS THE EASTERN SEABOARD FROM ATLANTA TO D.C. TO NEW YORK AS THE FAA REROUTES FLIGHTS TO AVOID THE STORMS. WITH MORE THAN 6,000 DELAYS AND 1,300 CANCELLATIONS NATIONWIDE. >> IT'S VERY FRUSTRATING. VERY, VERY FRUSTRATING. IF I WASN'T SUCH A BIG GIRL I'D ACTUALLY CRY. >> Reporter: IT COMES AS 84 MILLION FROM TENNESSEE TO NEW YORK ARE UNDER THE THREAT OF UP TO 75-MILE-PER-HOUR WINDS. >> LOOKS LIKE A BUS IS ON ITS SIDE. >> Reporter: HEAVY RAINS ARE ALSO BEING LOOKED AT AS A POTENTIAL CAUSE OF A DEADLY CHARTER BUS COLLISION JUST OUTSIDE HARRISBURG, PENNSYLVANIA WHERE THREE PEOPLE WERE KILLED AND DOZENS MORE WERE INJURED INCLUDING SEVERAL CHILDREN. >> IT HAD FLIPPED AND EVERYONE JUST KIND OF WAS SWUNG OFF TO THE SIDE. IT WAS -- IT WAS INTENSE. >> Reporter: THE SAME STORM SYSTEM MOVING EAST HAMMERED THE MIDWEST OVER THE WEEKEND. A CONFIRMED EF2 TORNADO WITH WIND SPEEDS AS HIGH AS 135 MILES PER HOUR, REDUCING SEVERAL HOMES IN CENTRAL ILLINOIS TO RUBBLE. NOW A MASSIVE SWATH OF THE COUNTRY IS BRACING FOR MORE. VAUGHN HILLYARD, NBC NEWS, WASHINGTON. >>> IN SOUTHERN CALIFORNIA AUTHORITIES ARE INVESTIGATING WHY TWO HELICOPTERS FIGHTING A FIRE COLLIDED LAST NIGHT. ONE OF THE CHOPPERS CRASHED, KILLING TWO FIRE OFFICIALS AND THE PILOT. THE OTHER CHOPPER WAS ABLE TO LAND SAFELY WITH TWO PEOPLE ON BOARD. THE AIRCRAFT WERE INVOLVED IN EFFORTS TO CONTAIN A SMALL BRUSH FIRE IN RIVERSIDE COUNTY. >>> TONIGHT LAWYERS FOR FORMER PRESIDENT TRUMP FIRING BACK AFTER A REQUEST FROM THE SPECIAL COUNSEL FOR A PROTECTIVE ORDER CONCERNING EVIDENCE IN THAT CASE INVOLVING THE 2020 ELECTION. KELLY O'DONNELL HAS LATE DETAILS. >> Reporter: TONIGHT A NEW PUSH IN THE LEGAL TUG OF WAR BETWEEN FORMER PRESIDENT TRUMP AND THE SPECIAL COUNSEL. >> IT'S FREE SPEECH. THIS MEANS THAT WE CANNOT EVER CRITICIZE. >> Reporter: IN A LATE FILING TRUMP LAWYERS COUNTERED JACK SMITH'S REQUEST FOR A PROTECTIVE ORDER, ARGUING IT VIOLATES HIS FIRST AMENDMENT RIGHTS. WORSE, IT DOES SO AGAINST ITS ADMINISTRATION'S PRIMARY POLITICAL OPPONENT DURING AN ELECTION SEASON. THE SPECIAL COUNSEL ASKED THE COURT TO IN EFFECT PUT UP GUARDRAILS TO PROTECT THE GOVERNMENT'S EVIDENCE, A CONSEQUENCE OF MR. TRUMP'S PROLIFIC SOCIAL POSTS. AMONG THEM, "IF YOU GO AFTER ME, I'M COMING AFTER YOU." THE SPECIAL COUNSEL WRITES, "IT COULD HAVE A HARMFUL CHILLING EFFECT ON WITNESSES OR ADVERSELY AFFECT THE FAIR ADMINISTRATION OF JUSTICE IN THIS CASE." MR. TRUMP FIRING OFF HIS OWN RESPONSE. "NO, I SHOULDN'T HAVE A PROTECTIVE ORDER PLACED ON ME BECAUSE IT WOULD IMPINGE UPON MY RIGHT TO FREE SPEECH." TRUMP ATTORNEY JOHN LAURO OUTLINED DEFENSE STRATEGY. >> MR. TRUMP HAD EVERY RIGHT TO PETITION GOVERNMENT AND ENFORCE HIS FIRST AMENDMENT RIGHTS. >> Reporter: AND MADE HEADLINES WHEN HE DESCRIBED MR. TRUMP'S PRESSURE ON PENCE TO HALT THE ELECTORAL COUNT. >> A TECHNICAL VIOLATION OF THE CONSTITUTION IS NOT A VIOLATION OF CRIMINAL LAW. THAT'S JUST PLAIN WRONG. >> Reporter: THE TRUMP LEGAL TEAM ARGUES A COURT ORDER SHOULD FOCUS ON ONLY THE MOST SENSITIVE GOVERNMENT DOCUMENTS AND NOT RESTRICT MR. TRUMP FROM TALKING ABOUT ALL OF THE EVIDENCE. THE JUDGE COULD RULE AT ANY TIME. LESTER? >> KELLY O'DONNELL, THANK YOU. THAT BRINGS US TO OUR EXCLUSIVE WITH MR. TRUMP'S TOP RIVAL, FLORIDA GOVERNOR RON DeSANTIS, WHO IS STILL TRYING TO MAKE A DENT IN MR. TRUMP'S LEAD. DURING THE INTERVIEW DASHA BURNS PRESSING DeSANTIS ABOUT HIS VIEWS ON THE 2020 ELECTION. >> Reporter: TONIGHT FLORIDA GOVERNOR RON DeSANTIS PREDICTING SUCCESS. DESPITE STRUGGLING TO GAIN TRACTION AGAINST THE REPUBLICAN FRONT-RUNNER. >> TRUMP'S LEAD HAS ONLY GROWN SINCE YOU BEGAN CAMPAIGNING IN EARNEST. IS IT POSSIBLE THAT YOU'RE POTENTIALLY JUST OUT OF STEP WITH WHAT GOP VOTERS ARE LOOKING FOR RIGHT NOW? >> SO IF I HAD A NICKEL FOR EVERY NAYSAYER I'VE HAD IN MY LIFE, I'D BE A VERY, VERY WEALTHY MAN. >> Reporter: AND ARGUING FORMER PRESIDENT TRUMP BRINGS DISTRACTIONS THAT HELP DEMOCRATS. >> IF THE ELECTION IS A REFERENDUM ON JOE BIDEN'S POLICIES AND THE FAILURES THAT WE'VE SEEN AND WE ARE PRESENTING A POSITIVE VISION FOR THE FUTURE, WE WILL WIN THE PRESIDENCY. IF ON THE OTHER HAND THE ELECTION IS NOT ABOUT JANUARY 20th, 2025 BUT JANUARY 6th, 2021 OR WHAT DOCUMENT WAS LEFT BY THE TOILET AT MAR-A-LAGO, IF IT'S A REFERENDUM ON THAT WE ARE GOING TO LOSE. >> CAN WE JUST PUT THIS TO BED SO YOU DON'T HAVE TO BE ASKED ABOUT THIS A MILLION MORE TIMES? YES OR NO, DID DONALD TRUMP LOSE THE 2020 ELECTION? >> WHOEVER PUT THEIR HAND ON THE BIBLE ON JANUARY 20th EVERY FOUR YEARS IS THE WINNER. >> BUT RESPECTFULLY, YOU DID NOT CLEARLY ANSWER THAT QUESTION. AND IF YOU CAN'T GIVE A YES OR NO ON WHETHER OR NOT TRUMP LOST THEN HOW -- >> OF COURSE HE LOST. >> TRUMP LOST THE 2020 ELECTION. >> OF -- JOE BIDEN'S THE PRESIDENT. >> Reporter: AND WE PRESSED DeSANTIS ON HIS NEW BORDER PROPOSAL TO ALLOW DEADLY FORCE AGAINST DRUG TRAFFICKERS DEMONSTRATING, QUOTE, HOSTILE INTENT. >> YOU'VE SAID IF CARTELS ARE TRYING TO RUN PRODUCT INTO THIS COUNTRY THEY'RE GOING TO END UP STONE COLD DEAD. HOW FAR MIGHT YOU TAKE THAT METHOD FOR PREVENTING ILLEGAL CROSSINGS IN GENERAL? >> IT'S SIMILAR TO LIKE IF YOU'RE IN THE MILITARY YOU HAVE RULES OF ENGAGEMENT. ANYONE THAT'S HOSTILE INTENT OR HOSTILE ACT, WHICH THE CARTELS ARE, YOU WOULD THEN ENGAGE WITH LETHAL FORCE. >> YOU YOURSELF WERE AN ADVISER TO NAVY S.E.A.L.s. YOU KNOW HOW HARD IT IS SOMETIMES WHEN IT COMES TO RULES OF ENGAGEMENT. HOW DO YOU DETERMINE IF IT'S A CHILD, A MOTHER OR -- >> OBVIOUSLY IF IT'S A CHILD YOU'RE NOT GOING TO DO THAT. BUT THEY HAVE -- >> BUT A PREGNANT MOM IN A BASEBALL CAP WITH A BACKPACK -- >> THEY HAVE INDICATIONS. I MEAN, IF YOU HAVE PEOPLE BLOW-TORCHING THROUGH A BORDER WALL, THAT IS NOT GOING TO BE -- >> BUT HOW DO YOU KNOW YOU'RE USING DEADLY FORCE AGAINST THE RIGHT PEOPLE? >> IT'S THE SAME WAY YOU WOULD DO IN ANY SITUATION. SAME WAY A POLICE OFFICER WOULD KNOW. SAME WAY PEOPLE OPERATING IN IRAQ WOULD KNOW. THESE PEOPLE IN IRAQ AT THE TIME THEY ALL LOOKED THE SAME. YOU DIDN'T KNOW WHO HAD A BOMB STRAPPED TO THEM. SO THOSE GUYS HAVE TO MAKE JUDGMENTS. >> Reporter: DeSANTIS OFTEN OUT ON THE TRAIL WITH HIS WIFE CASEY, A FORMER TV NEWS ANCHOR TOUTING HIS RECORD INCLUDING ON COVID. >> I SAW HIM STANDING UP TO PEOPLE IN WASHINGTON, D.C. WHO WERE TELLING HIM YOU'RE DOING IT WRONG, YOU HAVE TO SHUT DOWN THE BEACHES, YOU HAVE TO LOCK KIDS OUT OF SCHOOL. SO WHEN YOU SEE THAT FIRSTHAND AND YOU UNDERSTAND THE FIGHT THAT HE WAS TAKING, LIKE WHY WOULD I NOT BE IN THIS FIGHT? WHY WOULD I NOT WANT TO BE OUT THERE SINGING FROM THE ROOFTOP THAT THIS IS A GOOD DUDE? >> Reporter: AND THEIR THREE YOUNG KIDS ALSO ALONG FOR THE RIDE. CASEY DESCRIBING HOW HER HUSBAND SUPPORTED THEM WHEN SHE WAS DIAGNOSED WITH BREAST CANCER TWO YEARS AGO. >> HE WAS THERE FOR ME. AND HE WAS THERE TO GO PICK UP MY KIDS WHEN I COULDN'T. AND HE DID IT WITH HUMILITY AND HE DID IT WITH LOVE. AND I TELL YOU WHAT, YOU CAN'T ASK FOR A BETTER HUSBAND. >> DASHA JOINING ME. DASHA, DeSANTIS IS MAKING A BIG CAMPAIGN STOP LATER THIS WEEK. >> Reporter: LESTER, THE IOWA STATE FAIR KICKS OFF. BOTH DeSANTIS AND TRUMP EXPECTED TO BE THERE. AND THE DeSANTIS TEAM TELLS ME TRUMP'S LEAD IS SOFTER HERE THAN IT IS IN SOME OTHER STATES AND THEY CAN CHIP AWAY AT IT. LESTER? >> DASHA BURNS, THANK YOU. >>> TONIGHT IN UKRAINE OFFICIALS SAY A WOMAN HAS BEEN ARRESTED IN A PLOT TO ASSASSINATE PRESIDENT ZELENSKYY. AND THERE ARE ALARMING NEW DEVELOPMENTS INVOLVING JOINT RUSSIAN AND CHINESE PATROLS OFF THE U.S. COAST. HERE'S RICHARD ENGEL WITH THAT. >> Reporter: UKRAINIAN INTELLIGENCE SAYS THIS UNIDENTIFIED WOMAN IS A RUSSIAN SPY CAPTURED WHILE CARRYING OUT A PLOT TO ASSASSINATE PRESIDENT ZELENSKYY DURING THIS TRIP TO MYKOLAIV LAST MONTH. SHE WAS ALLEGEDLY TRACKING HIS MOVEMENTS SO HE COULD BE TARGETED WITH A RUSSIAN AIRSTRIKE. THE KREMLIN SO FAR NOT COMMENTING ON THE ACCUSATIONS. WITH ITS COUNTEROFFENSIVE STALLED, UKRAINE IS PUSHING THE WAR BEYOND ITS BORDERS. THERE WAS A SEA DRONE ATTACK LAST WEEK NEAR A RUSSIAN PORT. BUT RUSSIAN PRESIDENT VLADIMIR PUTIN AND HIS ALLY CHINA'S PRESIDENT XI ARE PROJECTING THEIR POWER ABROAD TOO, SENDING AN ALARMING NEW MESSAGE TO THE UNITED STATES, UKRAINE'S MAIN BACKER. A PATROL OF 11 CHINESE AND RUSSIAN WAR SHIPS CRUISED TOGETHER NEAR ALASKA. THE PENTAGON SAYING THERE WAS NO DIRECT THREAT, BUT SENDING FOUR DESTROYERS AND A RECONNAISSANCE PLANE AS A WARNING. THE THREAT TO ALASKA IS GROWING. LESTER TALKING TO THE TOP-RANKING U.S. MILITARY OFFICER THERE JUST LAST MONTH. >> HOW DO YOU SEE THE CHINESE THREAT, THE NORTH KOREAN THREAT? >> I SEE THE CHINESE THREAT EVER INCREASING IN THE PACIFIC. I ALSO -- I WATCH THEIR COOPERATION WITH THE RUSSIANS. I LOOK AT THE RUSSIAN ACCESS IN THE ARCTIC WITH THEIR BASES. AND I DO HAVE CONCERNS. >> Reporter: CHINA SAYS THE PATROLS WERE NOT HOSTILE. CHINA ALSO TOOK PART IN UKRAINE PEACE TALKS IN SAUDI ARABIA OVER THE WEEKEND. NEGOTIATORS ONLY AGREEING TO MEET AGAIN. LESTER? >> RICHARD ENGEL, THANK YOU. >>> WITH TENSIONS SOARING IN THE PERSIAN GULF THE U.S. HAS DEPLOYED THOUSANDS OF MILITARY PERSONNEL AND TWO SHIPS TO PROTECT OIL TANKERS. COURTNEY KUBE IS FOLLOWING THIS FROM THE PENTAGON. AND COURTNEY, THIS IS ALL A RESPONSE TO A GROWING THREAT FROM IRAN. >> Reporter: YEAH, THAT'S RIGHT, LESTER. THOSE TWO U.S. WARSHIPS WITH MORE THAN 3,000 U.S. SAILORS AND MARINES ARE NOW IN THE RED SEA, ORDERED THERE AFTER IRANIAN NAVAL VESSELS TRIED TO STOP, BOARD AND SEIZE TWO OIL TANKERS NEAR THE STRAIT OF HORMUZ LAST MONTH, EVEN FIRING ON ONE AND STRIKING ONE OF THOSE SHIPS. IN BOTH CASES THE IRANIAN BOATS TURNED AWAY AFTER A U.S. MILITARY SHIP AND AIRCRAFT ARRIVED. THAT FOLLOWED AN APRIL INCIDENT WHEN MASKED IRANIAN COMMANDOS SEIZED AN OIL TANKER IN THE GULF OF OMAN. IRAN'S FOREIGN MINISTRY SAYING THE U.S. MILITARY PRESENCE ONLY FUELS INSTABILITY IN THE REGION. IRAN HAS EITHER SEIZED OR ATTEMPTED TO SEIZE NEARLY 20 SHIPS IN THE PAST TWO YEARS. LESTER? >> COURTNEY KUBE, THANK YOU. >>> IN 60 SECONDS DISTURBING QUESTIONS AFTER THE BRAWL AT A RIVERFRONT DOCK IN MONTGOMERY, ALABAMA. WAS RACE A FACTOR IN THE FIGHT? WHAT THE VIDEOS SHOW, AND THE GROWING >>> CAUGHT ON CAMERA IN TEXAS, A FIREBALL RISING FROM MASSIVE EXPLOSIONS AT A SHERWIN WILLIAMS PAINT FACTORY OUTSIDE DALLAS. OFFICIALS SAY ONE EMPLOYEE WAS INJURED AND TREATED ON THE SCENE OVERNIGHT. A HAZMAT TEAM WAS DEPLOYED TO MONITOR AIR QUALITY. THE CAUSE IS UNDER INVESTIGATION. >>> AND ALSO CAPTURED ON VIDEO, A VIOLENT BRAWL IN ALABAMA THAT APPEARED TO INVOLVE A GROUP OF WHITE BOATERS ATTACKING A BLACK DOCK WORKER. TONIGHT POLICE HAVE ISSUED ARREST WARRANTS IN THE CASE. HERE'S PRISCILLA THOMPSON. >> Reporter: OUTRAGE IS GROWING ACROSS THE COUNTRY OVER THESE NOW VIRAL VIDEOS APPEARING TO SHOW MORE THAN A DOZEN PEOPLE IN AN ALL-OUT BRAWL ON THE DOWNTOWN MONTGOMERY RIVERFRONT. NO ARRESTS HAVE BEEN MADE, THE MAYOR SAYS, BUT INVESTIGATORS HAVE ISSUED FOUR ARREST WARRANTS AND SAY THEY'RE REVIEWING VIDEOS OF THE INCIDENT AND THAT MORE COULD BE COMING. >> IT'S SOMETHING THAT SHOULDN'T HAVE HAPPENED AND IT'S SOMETHING THAT WE'RE INVESTIGATING RIGHT NOW. >> Reporter: THE CHAOS UNFOLDED SATURDAY NIGHT AFTER WITNESSES SAY A WORKER ASKED A GROUP MULTIPLE TIMES TO MOVE THEIR PONTOON SO A COMMERCIAL RIVERBOAT COULD DOCK. KRISTA OWENS SAYS SHE FILMS THIS VIDEO FROM ON BOAT THE RIVERBOAT. >> THEY'RE MAD THIS GUY WHO CAME OFF OUR BOAT IS UNTYING HIS BOAT AND TOUCHING IT. BUT IT NEEDED TO MOVE. >> Reporter: A BRAWL STARTS, AND WITHIN SECONDS SEVERAL PEOPLE APPEAR TO JOIN IN. >> WITNESSING OUR POOR CREWMAN BEING ATTACKED BY THESE GUYS. AND WE COULDN'T DO ANYTHING ABOUT IT. >> YEAH, THESE WHITE FOLKS -- >> Reporter: AFTER THE RIVERBOAT DOCKS FIGHTING ERUPTS AGAIN. POLICE ON THE GROUND STRUGGLING TO CONTAIN THE CHAOS. BUT EVENTUALLY GETTING SOME IN HANDCUFFS. THE MAYOR NOW PLACING THE BLAME ON SEVERAL RECKLESS INDIVIDUALS FOR ATTACKING A MAN WHO WAS DOING HIS JOB AND VOWING THAT JUSTICE WILL BE SERVED. THE MAYOR DECLINED TO SAY WHETHER INVESTIGATORS BELIEVE THE FIGHT WAS RACIALLY MOTIVATED, ADDING ONLY THAT THE INVESTIGATION IS ONGOING. LESTER? >> ALL RIGHT. PRISCILLA, THANK YOU. >>> UP NEXT, NEW WARNINGS ABOUT THE DANGERS OF NURSING PILLOWS WHEN USED THE WRONG WAY. OUR NBC NEWS INVESTIGATION INTO DEADLY INCIDENTS INVOLVING THE PILLOWS AND WHAT EXPERTS SAY PARENTS NEED TO KNOW. >>> BACK NOW WITH OUR NBC NEWS INVESTIGATION INTO A POPULAR BABY PRODUCT, NURSING PILLOWS. OUR REPORTING REVEALS THEY'VE BEEN LINKED TO MORE INFANT DEATHS THAN THE GOVERNMENT HAS ANNOUNCED. NOW THE GOVERNMENT IS PLANNING NEW SAFETY REGULATIONS. VICKY NGUYEN HAS WHAT PARENTS NEED TO KNOW. >> Reporter: TAYLOR WELLS RETURNED TO WORK WHEN HER DAUGHTER AUTUMN WAS SIX WEEKS OLD. ENTRUSTING HER BABY TO DAYCARE STAFF NEAR HER MISSISSIPPI HOME. >> SHE WAS SWEET AND SHE WAS HAPPY. SHE LAUGHED ALL THE TIME. >> Reporter: BUT IN MARCH OF 2022 TAYLOR'S PHONE RANG AT WORK. >> THE FIRST THING I HEAR IS "YOU NEED TO GET TO THE HOSPITAL. AUTUMN'S NOT BREATHING." SO YOU KNOW, OF COURSE I RUN AS FAST AS I CAN. I RAN INTO THE EMERGENCY ROOM. AND I COULD TELL -- I COULD SEE THEM WORKING ON HER. >> Reporter: FOUR-MONTH-OLD AUTUMN WAS FOUND FACE DOWN ON A NURSING PILLOW, COVERED COMPLETELY WITH A BLANKET ACCORDING TO HER DEATH CERTIFICATE. IT SHOWED SHE DIED OF ASPHYXIATION. >> IT'S HARD TO EVEN DESCRIBE WHAT HAPPENS WHEN THEY TELL YOU THAT YOUR CHILD IS NO LONGER WITH YOU. >> Reporter: MORE THAN A MILLION NURSING PILLOWS ARE SOLD IN THE U.S. EACH YEAR. THEY'RE DESIGNED TO POSITION BABY AND MOM COMFORTABLY FOR BREASTFEEDING. BUT AN NBC NEWS ANALYSIS OF INTERNAL FEDERAL DOCUMENTS AND PUBLIC RECORDS FOUND MORE THAN 160 BABIES HAVE DIED IN INCIDENTS INVOLVING NURSING PILLOWS SINCE 2007, MOST COMMONLY WHEN THE PILLOWS WERE USED AS SLEEPING DEVICES OR TO PROP BABIES UP. >> BABIES ARE DYING IN THE PRODUCTS, AND THEY SHOULDN'T BE. >> Reporter: COMMISSIONER RICH TRUMKA WITH THE CONSUMER PRODUCTS SAFETY COMMISSION SAYS LATER THIS MONTH THE AGENCY WILL PROPOSE ITS FIRST SAFETY REGULATIONS FOR NURSING PILLOWS. >> CPSC HAS KNOWN ABOUT INFANT DEATHS LINKED TO THESE NURSING PILLOWS FOR DECADES. WHY HASN'T THE AGENCY TAKEN ACTION SOONER? >> SO WHEN I GOT HERE A YEAR AND A HALF AGO, THE AGENCY HAD RECOGNIZED THE HAZARD AND HAD ALREADY COMMISSIONED A STUDY. >> Reporter: RESEARCHERS FOUND NURSING PILLOWS THAT WERE FIRMER WITH MORE DEFINED EDGES WERE SAFER. >> SOME OF THESE PRODUCTS HAVE LABELS WITH PICTURES SHOWING DIFFERENT WAYS TO USE THE NURSING PILLOW THAT IS NOT RELATED TO BREASTFEEDING. IS THAT OKAY OR NOT? >> I'VE GOT GREAT CONCERNS ABOUT THAT. >> Reporter: LABELS WARN AGAINST ALLOWING BABIES TO SLEEP IN THE PILLOWS. >> ARE THE PILLOWS THE PROBLEM, OR IS THE PROBLEM THAT PEOPLE AREN'T USING THEM PROPERLY? >> WE'RE NOT GOING TO BLAME THE PARENTS WHO ARE USING THESE PILLOWS. IF A PRODUCT IS SOLD TO YOU AND IT LOOKS LIKE IT CAN BE USED FOR SLEEP, IT SHOULD BE SAFE FOR SLEEP. AND WE WANT TO MAKE SURE THAT THINGS THAT AREN'T FOR SLEEP DON'T LOOK LIKE YOU CAN LAY YOUR BABY DOWN IN THEM. >> Reporter: BOPPY AND LEACHCO, THE MAKERS OF TWO POPULAR NURSING PILLOWS, POINTED NBC NEWS TO AN INDUSTRY-FUNDED GROUP WHICH SAID DRASTICALLY CHANGING THE SHAPE OF THE VAST MAJORITY OF NURSING PILLOWS COULD HAVE A NEGATIVE IMPACT ON BREASTFEEDING. THE GROUP IS FUNDED IN PART BY BOPPY. LEACHCO IS A MEMBER. EMERGENCY MEDICINE PEDIATRICIAN DR. LOIS K. LEE SAYS BABIES SHOULD BE PLACED ON THEIR BACKS ON A SOFT SURFACE TO SLEEP WITHOUT ANY SOFT OBJECTS. >> MY RECOMMENDATION TO PARENTS IS ABSOLUTELY USE IT TO SUPPORT BREASTFEEDING SO YOU'RE COMFORTABLE AND THE BABY'S COMFORTABLE BUT AFTER THAT PUT IT AWAY. >> Reporter: IN JUNE TAYLOR WELLS WELCOMED BABY ELIZA. SHE'S HOPEFUL ANY NEW GOVERNMENT RULES ON NURSING PILLOWS WILL INCLUDE A BROAD CAMPAIGN TO REACH PARENTS AND CAREGIVERS EVERYWHERE. >> THAT'S WHAT WE REALLY NEED. WE NEED EDUCATION BECAUSE THAT IS -- THAT IS WHAT IS GOING TO SAVE LIVES. THAT'S WHAT'S GOING TO SAVE BABIES. >> Reporter: FOR NOW EXPERTS SAY ONLY USE NURSING PILLOWS WHILE BREASTFEEDING AND NEVER LEAVE A BABY ALONE IN ONE. VICKY NGUYEN ALWAYS REMEMBER. ANNE THOMPSON, NBC NEWS. >> AND THAT'S "NIGHTLY NEWS" FOR THIS MONDAY. THANK YOU FOR WATCHING. I'M LESTER HOLT.