Maryland will take a small step toward less restrictive marijuana laws by allowing the drug's use to alleviate certain medical conditions. The law restricts such use to tightly regulated programs operated out of academic medical centers.

The state is also adopting its most comprehensive set of campaign finance reforms since the early 1990s. Among other provisions, the measure requires more timely reporting of contributions and seeks to close a loophole that has allowed some business owners to exceed donation limits many times over by using multiple corporations to give to candidates. It also increases donation limits for the first time in two decades to account for inflation.

Other laws that take effect Tuesday seek to protect newborn babies and users of swimming pools. One requires health professionals to tip off local social services departments when a newborn shows signs of exposure to illegal drugs or symptoms of fetal alcohol syndrome. The other tells publicly operated swimming pools to equip themselves with external defibrillators that can be used to shock a heart back into beating after a water rescue.

Legislators also stood up for another form of swimmer: the type with fins and razor-sharp teeth. In an effort to curb overfishing, a new law will ban the possession or sale of shark fins. Proponents contend that tens of millions of sharks are killed each year for their fins alone.

Tami Santelli, Maryland director of the Humane Society of the United States, said while sharks might not be the most appealing of animals, they play a crucial role.

"Their survival really impacts all kinds of species beneath them," she said. In the Chesapeake Bay, their decline has led to an abundance of cownose rays that has been devastating to the oyster population.

Baltimore Sun reporters Kevin Rector and Erin Cox contributed to this article.

Michael.dresser@baltsun.com

New laws on the books

These are among the hundreds of new Maryland laws taking effect Tuesday:

Cellphones

Drivers are already prohibited from using hand-held cellphones, but the new law lets police stop them for that offense alone.

Gun bill

Gov. Martin O'Malley's legislation bans the sale of certain guns classified as assault rifles and requires a license and fingerprints to purchase handguns. Gun rights groups have sued to block it.

Death penalty repeal

The law does not affect the five men now on death row, but no one else can be sentenced to death in Maryland.

Newborn drug exposure

Requires health care practitioners involved in delivering babies to report when newborns have been exposed to illegal drugs.

Defibrillators at pools

Requires public swimming pools to have defibrillators and staff trained to use them in medical emergencies.