( CNN ) -- At least two people were killed and four were critically injured Monday in a plant accident in Omaha , Nebraska , authorities said . The incident happened about 10 a.m. CT at International Nutrition , a company that produces feed and other products for livestock and poultry . `` I heard the explosion and stuff started falling , so I ducked for cover , '' worker Nate Lewis told CNN affiliate KETV . `` It was pitch black in there . All I could see was fire . I had to feel my way out of the place . I could n't see anything . '' There were 38 people at the plant at the time of the incident , interim Omaha fire Chief Bernard Kanger said . Ten of the injured people needed a trip to the hospital , the chief said , adding that four were initially in critical condition . Seven other people were treated at the scene , he said . Kanger said two people had died . One was identified by police as 53-year-old Keith Everett . The other body remained in the facility after officials called off recovery efforts due to cold weather and high winds . Both of the workers who died were discovered on the second floor . The second body should be removed Tuesday , but it will be a very labor-intensive recovery , Kanger said . The chief said he believed all other people at the plant had been accounted for as of Monday night , but they will double-check Tuesday to make sure there were no visitors or workers who had dropped by . An employee told KETV that he heard noises , saw fire and sprinted for his life . `` I just heard a crack pop and big ball of fire , and I just took off running when I heard the first crack , '' worker Jamar White `` That 's all I could do was get out of the way and make sure I was OK. '' School , neighborhood evacuated after Tennessee plant fire . Kanger said the cause of the industrial accident is under investigation , and officials are not to prepared to say it was caused by an explosion . `` What we do know is there was a significant event that occurred , causing catastrophic failure of the structure , '' Kanger said . He said that the second and third stories of the facility collapsed , sending tens of thousands of pieces of concrete , steel and sheet metal pounding through to the first floor . About 50 firefighters responded to the 911 call . One plant worker , who was conscious and talking , had to be rescued from under debris by firefighters who were unsure whether conditions were stable . It took about 10 to 15 minutes for emergency crews to cut through the concrete and steel . Another two workers were stranded on a beam , Kanger said . There were at least four ladder rescues , he added . A spokesman for the Occupational Safety and Health Administration said OSHA investigators were at the plant , where part of the building had collapsed . Scott Allen said it is too early to determine the cause of the accident . According to OSHA records obtained by CNN , International Nutrition Inc. has been cited for 35 OSHA violations over the past 40 years -- most notably for seven violations following the August 20 , 2002 , death of a 45-year-old male employee who fell into a mixing tank and was mutilated by an auger . International Nutrition also was fined $ 10,000 by OSHA in 2013 after a lengthy investigation found six violations , including two related to electrical safety standards for machines that were undergoing maintenance , Allen said . International Nutrition is n't on OSHA 's Severe Violator Enforcement Program , a list of companies that have knowingly disregarded safety regulations . OSHA investigators will lead the accident investigation , while Omaha police will lead the death investigations , Kanger said . Kanger said International Nutrition had cooperated with investigators . 5 killed , 12 injured in explosion at chemical plant in Japan . CNN 's Mike Ahlers contributed to this report .
NEW : Police say body of Keith Everett recovered , one still in building . Chief says despite reports , they are unable to say there was an explosion . Company has been cooperative with investigators , he says . OSHA says too early to say what caused the incident .