THE APPALLING security lapses at the Prince George’s County jail, as illustrated last week by the eye-opening reporting of The Post’s Aaron C. Davis, constitute a blatant management failure and a risk to public safety. A key witness to a double killing was executed last December shortly after visiting his brother at the jail, where he was unexpectedly confronted by the very defendant against whom he was planning to testify. Prosecutors believe the victim was slain on the orders of the man who confronted him in jail.

In response to this outrage, it would be natural to expect corrections officials to have ordered a sweeping review of security procedures at the jail, including protocols involving visitors, the monitoring of inmates’ conversations with visitors and telephone usage by inmates.

There is no evidence that this has happened. Rather, a spokeswoman for the county Corrections Department told The Post that she was unaware of any current investigation of jail operations.

Other authorities may be less complacent. The Post article revealed that investigations from outside the department have turned up an array of administrative failures. Now it is up to county corrections officials to act.

The shortcomings at the jail, which houses about 1,300 inmates, are mind-boggling. Unlike most large jails in the Washington area and many others elsewhere, the Prince George’s jail does not directly monitor, videotape or record visits to inmates by friends or family, and it does not even have the technology in place to do so.

Nor is there a foolproof system to enable officials to listen in on inmates’ phone calls. To beat the monitoring system, inmates have simply swapped the individually coded debit cards they use to place calls, leading the authorities to eavesdrop on the wrong inmates. Can it really be so complicated to fix that?

What’s more, there is evidence, The Post reported, that guards have been smuggling cellphones into the jail for inmates, as many apparently did at the Baltimore jail.

Prince George’s corrections officials seem unconcerned. Rather than installing cameras or video terminals to monitor visits with inmates or updating cellphone-access procedures, plans are afoot to modernize the kitchen at the 28-year-old facility.

If corrections officials cannot recognize the urgency of the problems at the jail, then more senior officials in the county must intervene, and quickly. The shenanigans at Baltimore’s jail have made it into a national disgrace. The same must not be allowed to happen in Prince George’s.