Five years ago, a team of New York detectives started Operation Nexus, which rallies businesses to assist in NYPDs efforts against terrorist activity. The group is ramping up the project, and self-storage facilities are included in the call.

More than 25,000 businesses have been contacted since the operations inception. According to spokesman Paul Browne, participants are "manufacturers or service providers whose products have been used, or the use had been contemplated, in actual or planned terrorist attacks." Top candidates include companies that deal in the sale of potentially harmful chemicals. But NYPD is also approaching building managers to be on the lookout for anything unusual involving such substances, including large or multiple containers that turn up in trash cans or dumpsters. Self-storage facilities are among those approached to cooperate.

Over the past several months, NYPD has held a series of briefings for business owners, private security officials and landlords about the possibility of terrorists creating and storing homemade bombs.