1.   NASA also revamped its safety procedures at JSC and has installed warning sirens around the facility to be sounded in case of emergency, Harlan said.

2.   Though the siren was installed more than two months ago, Kraus said he is still working the bugs out.

3.   Air raid sirens were being installed in some areas.

4.   Warning sirens have been installed around the facility, and thousands of radios were distributed to alert residents in case of an accident.