They inspect passports to determine whether people are legally eligible to enter and to verify their citizenship status and identity. Immigration inspectors also prepare reports, maintain records, and process applications and petitions for immigration or temporary residence in the United States. Customs inspectors enforce laws governing imports and exports. Stationed at airports, seaports, and border crossing points, they examine, count, weigh, gauge, measure, and sample commercial cargoes entering and leaving the United States to determine admissibility and the amount of tax that must be paid. They also inspect baggage and articles worn by passengers and crew members to insure that all merchandise is declared, proper duties are paid, and contraband is not present.
Postal inspectors observe the functioning of the postal system and recommend improvements.
They investigate criminal activities such as theft and misuse of the mail. In instances of suspected mismanagement or fraud, they conduct management or financial audits. They collaborate with other government agencies, such as the Internal Revenue Service, as members of special task forces. Aviation safety inspectors may inspect aircraft and equipment manufacturing, maintenance and repair, or flight operations procedures. They usually specialize in either commercial or general aviation aircraft.