No one has ever been safe. This is a consulting firm, as soon as your project ends (or someone else wins the contract) you are highly likely to have your hours reduced or to be let go unless there is another project that can absorb you. This happens constantly, Maryland is bigger, but odds are that whomever won the new contract will need some of the staff to ensure continuity, so at least there is that.
AECOM really doesn't care about you long term if you can't either bring in a ton of work or can maintain your bilability. You could say the same about other consulting firms, though they may have more (or less) tolerance for events that affect your bilability.
I'm not actually sure that higher level management is much safer, they just have much quieter "voluntary" exits.