Los Angeles ( CNN ) Even as major airports across the country clamp down on employee screening , a lone wolf could still potentially slip through security , a top airport official said . Email your story ideas and tips to CNNtips @ cnn.com . Patrick Gannon , police chief of Los Angeles International Airport , said the 54,000 employees with security badges undergo recurring criminal background checks and random screening . But even that may not be enough . `` I agree that in any airport throughout the United States and here also , there is never a 100 % guarantee that somebody who wanted to do something illegal or wrong could n't make that happen , '' Gannon said . Only two major airports in the United States -- Miami and Orlando -- conduct full employee screening by requiring all employees with access to secure areas to pass through a metal detector , a CNN investigation found . Other airports like Los Angeles conduct random screenings . Many airports do n't do any screenings at all other than a criminal background check before employees are hired . The crackdown on employee screening comes after the arrest of a Delta baggage handler and passenger accused of gun smuggling at Atlanta 's Hartsfield Jackson International Airport in December . Both Atlanta and Los Angeles have since begun restricting access by closing access doors that lead to the airfield . Nevertheless , Gannon acknowledged that the potential of a lone wolf committing a crime at the airport worries him . `` It concerns me all the time , '' he said . With so many employees , `` [ T ] here is no way that you are going to have the ability to screen every single person that comes to work in the airport . '' At LAX , employees punch in a code and swipe their badge to access the airfield . Gannon said about 18 out of approximately 300 access doors have been closed as the airport evaluates employee screening procedures . He said , `` the more you limit the access doors , the more you can focus things like spot checks and screenings and cameras . '' Even at Miami International Airport , Gannon said , `` they still ca n't 100 % say that they can keep contraband or any type of item out of their restricted area . '' Lauren Stover , Miami airport security director , agreed that ID badges alone `` are not enough [ to ] stop malicious intent . '' `` You can vet employees for basic information on their backgrounds , but it 's not going to prevent them from carrying out some kind of malicious activity against an airport . And airports need to know their threats . For us , we have threats from criminal activity to being targets of a terrorism attack , '' Stover said . In the wake of congressional scrutiny of airport employee screening procedures , private security guards at Atlanta 's airport last month began checking employee bags as the first step toward moving toward full employee screening . The airport also plans to reduce the number of secure access doors from 70 to 10 . `` In the last six months ... people are being recruited to engage in terrorist acts , '' said Miguel Southwell , the airport 's general manager . `` People are being recruited from the United States . So now we have a greater insider threat . '' The TSA is conducting a review of the feasibility of full employee screening , although previous government studies have concluded that would be too expensive and inefficient . Watch Anderson Cooper 360° weeknights 8pm ET . For the latest from AC360° click here .
Airports are stepping up employee screening . Still , there 's never a 100 % guarantee of safety , airport official says . CNN investigation found only two major Los Angeles airports conduct full employee screenings .