Utah's prison population is nearing its capacity of some 6,700 inmates and a hoped-for release valve won't be available, the head of the prison system warned legislators Tuesday.

Tom Patterson, executive director of the Utah Department of Corrections, said the ranks of the incarcerated are growing by a net of 21 inmates a month.

The prison system currently is 71 male inmates under its operating capacity -- which is 95 percent of its total number of beds -- and 40 female inmates below that system's capacity, he said.

"We'll hit that fairly soon, again, with no plan for future inmates," Patterson told lawmakers.

A 300-bed center intended to house inmates who violate their parole, which was postponed last session, may now be on hold indefinitely, as the company that had been hired to build the center has told the department it can no longer construct the facility.

The prison system also lost a planned 192-bed expansion in Gunnison, a 40-bed transition facility and an 80-bed diagnostic center.

Patterson said the department has taken a series of steps that have kept down its incarceration rates, which typically rise during an economic downturn. "We could be in a world of hurt" otherwise, he said.

But Patterson said he remains upbeat about the department and his staff's willingness to persevere.

The prison system was just one of several departments that presented its budget snapshot to the Legislature's main budget committee. Lawmakers are staring down the daunting task of balancing a budget that is projected to have as much as an $850 million shortfall.

That means $460 million in cuts planned last session to take effect next year will most likely not be reversed and lawmakers may have to look to additional budget slashing.

"No agencies should plan on receiving large influxes of additional revenue," said House budget chairman Ron Bigelow, R-West Valley City. "Quite the contrary, it appears we may need to go ahead and look at possible reductions. So when everyone is thinking that maybe that $400 million in cuts may not take place, they need to look at the projections for revenue again."

Amanda Smith, the new director of the Department of Environmental Quality, said the agency has cut its travel budget and is taking longer to respond to the companies it permits throughout the state. The radiation control division is stretched thin, but the department's duty to monitor air and water is not impaired, she said.

Utah Tax Commission Executive Director Rodney Marrelli said his agency has tried to cut costs by doing more online, like vehicle registrations and income tax filings. His concern, he said, is that tax enforcement might slip because of the tight budget.

"Nobody screams when we don't come to audit them. Nobody screams when we don't come to try to collect their income taxes," he said. "With lack of enforcement comes more laxness in filing and paying taxes that are due."

He said Utah taxpayers might see the effects of the budget cuts when the commission can't hire seasonal workers next year to process tax returns. "That will slow down the deposits to some extent and possibly slow down some of the refunds to some of your constituents," he said.