CHICAGO (CBS) — One of Illinois’ biggest engineering firms could find itself fighting for its survival.

As WBBM Newsradio’s Bob Conway reports, the Illinois Department of Transportation has banned McDonough Associates Inc. from getting any state work for three years. The Chicago Sun-Times reports the firm stands accused of theft by overbilling by more than $1.9 million.

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LISTEN: WBBM Newsradio’s Bob Conway reports

The department has sent a bill back to the 45-year-old firm, and has referred its findings to authorities for possible criminal prosecution, the Sun-Times reported.

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The Sun-Times says similar action may be taken by the Illinois Toll Highway Authority and the City of Chicago, with which it also has millions of dollars in contracts.

The firm was founded by James J. McDonough, who served as Streets and Sanitation commissioner and Chicago Transit Authority Board chairman under the late Mayor Richard J. Daley, the Sun-Times reported.

The firm admits that it made what it calls “some honest mistakes in accounting procedures,” but denies stealing any money, the Sun-Times reported.

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McDonough also says if the suspension survives a court challenge, it amount to a death sentence, the newspaper reported.