CONCORD, N.H. (AP) — Incoming mail to New Hampshire prison inmates is getting a closer look after people at other correctional facilities got sick.

The New Hampshire Department of Corrections says it is holding all mail, including packages, for a short time as it implements new safety measures. The move was prompted by reports from Ohio, Arkansas and Pennsylvania about inmates and staff becoming ill after coming into contact with unknown substances.

The mail will be held while the department distributes new equipment to increase the safety of those who screen the mail, which adds up to hundreds and letters and packages each day.