Small amounts of marijuana may be legal today, but you’ll be fined for lighting up in public and risk arrest if you carry the drug onto federal property, such as courthouses and national park and forest land.

In some cases, you could lose your job if your employer doesn’t want you using marijuana.

As for smoking on college campuses? Forget about that, too.

“There are a lot of problems,” said Yakima County Prosecutor Jim Hagarty, referring to conflicts between the groundbreaking state measure legalizing pot and federal law that keeps the drug illegal.

On Wednesday, the U.S. Justice Department reminded people that marijuana remains illegal under the federal Controlled Substances Act. Carrying or using it in places, such as Mount Rainier National Park or the Wenatchee National Forest, remains against the law.

The federal agency also noted it is reviewing the legalization measures recently passed in Colorado and Washington.

Washington’s new law — which went into effect at 12:01 a.m. today after being approved by 56 percent of state voters in November — allows possession of up to an ounce of marijuana, or 28 grams, providing the holder is 21 years or older. Under the law, it can be consumed only in private residences.

The new law also allows possession of up to 16 ounces of a marijuana-infused products in solid form, such as brownies, and 72 ounces of a marijuana-infused products in liquid form, such as beverages. There are no changes to the state’s medical marijuana law, which allows qualifying patients with terminal or debilitating conditions to possess and grow marijuana plants.

Police say the complexities of the new law may create more confusion for users than for officers. Smoking marijuana in public could land users a $103 fine.

“It’s for private consumption in private residences,” Yakima Police Capt. Rod Light said. “It’s not open to be consumed in public places.”

Drivers pulled over on suspicion of driving stoned may have their blood drawn to test for levels of THC, the main psychoactive component in marijuana.

A blood sample of 5 nanograms of active THC per milliliter is already grounds for charging someone for driving under the influence, but police still need probable cause to stop and test a suspect.

The new law also raises questions about employers’ substance abuse policies. Yakima attorney Gary Lofland, who represents employers and specializes in labor employment issues, said he is advising clients to draft narrow policies.

Lofland said substance abuse policies that leave ambiguities in how much alcohol or THC an employee can have in their system could make it difficult to administer the policy.

“As a result, I’m recommending people have zero tolerance for any marijuana or alcohol in their employees,” Lofland said.

Lofland said he hasn’t spoken with any employers considering loosening their substance abuse policies because of the new law. He said businesses that benefit from federal dollars could have those benefits taken from them if they fail to comply with the Drug-Free Workplace Act.

Several state colleges, including Central Washington University and Washington State University, on Wednesday issued firm reminders that marijuana remains forbidden on campus.

If the university disregards federal law and allows marijuana use at its facilities, it risks losing more than $93 million in federal funding, CWU’s Dean of Student Success Sarah Swager said in a statement.

The state Liquor Control Board has until Dec. 1, 2013, to establish rules for growing, distributing and selling marijuana at state-run stores. The state Office of Financial Management projects that the 25 percent excise tax, combined with retail sales and the B&O tax, would generate more than $575 million in new state revenue annually.

About $182 million would go to the state general fund, $34 million to local governments and $366 million to health care, education and prevention.

But until the state gets in the business, recreational marijuana users will still be purchasing the product from illegal dealers who law enforcement will continue to pursue.

“We still have the power to arrest someone with scales and large amounts,” Yakima County Sheriff Ken Irwin said. “It’s still illegal to manufacture.”

Irwin and Light said the new law would not hinder efforts to shut down black market dealers.

“Our job in the police department is to put pressure on their operations at any level,” Light said.

However, counties and cities across the state have begun to dismiss charges against those whose cases may not have been illegal under Initiative 502.

Hagarty said Yakima County is in the process of dismissing 54 misdemeanor possession charges; city of Yakima spokesman Randy Beehler said as many as 14 such city cases will be dropped.

Both county and city officials said some misdemeanor possession cases won’t be dropped based on a suspect’s previous criminal history or if the charge was associated with other violations, such as driving under the influence of alcohol.

“The conduct at the time it occurred was illegal,” Hagarty said. “(The law) does not retroactively apply to any of those cases.”

• Contact Mike Faulk at 509-577-7675 or mfaulk@yakimaherald.com. Follow him on Twitter at twitter.com/Mike_Faulk.