OTTAWA (CP) - Smoking marijuana does not seem to cause lung cancer,
emphysema or cause birth anomalies in fetuses, a prominent U.S. researcher
told a Senate committee Monday.

John P. Morgan of City University of New York Medical School said
heavy marijuana smokers do show some symptoms of lung damage, such as
coughing, frequent colds and bronchitis, but not the life-threatening
conditions seen among tobacco smokers.

''We are some 30 to 40 years into this marijuana epidemic and still
have not seen evidence of pulmonary cancer in marijuana smokers.''
He was speaking before a special Senate committee reassessing
federal legislation and polices on marijuana.

Morgan said there are reasons to believe the heavy smoker of
cannabis will not succumb to emphysema, a condition frequent among
cigarette smokers.

He said cannabis contains just as many harmful compounds and
irritants as tobacco, but even heavy marijuana smokers - those who consume
four to six joints daily - don't smoke nearly as much as tobacco smokers.

''The critical issue is the amount of smoke inhaled.''

He said marijuana smokers have slightly more respiratory complaints
than non-smokers, but the difference is so small that it is of no practical
significance.

Morgan also criticized research purporting to show fetal damage
among women who smoke marijuana and scoffed at the theory that marijuana is
a gateway leading to hard drugs.

''Many critics in the United States have decided that marijuana
incites some biochemical trance that leads people to tramp the streets
looking for heroin and cocaine.''

But statistics show that most marijuana smokers never go on to other
drugs, he said. ''There is no gateway, there is no credible gateway theory.''

He said prohibition of marijuana only makes young people more
interested in trying it.

Rates of marijuana use in The Netherlands, where the drug is freely
available, he said, are lower than in the United States where it is banned.

Morgan conceded that marijuana smokers are impaired for several
hours after smoking.

People who are high should not drive, babysit, mow the lawn or enter
into marital contracts, he said.

He attributed opposition to decriminalization of marijuana to what
he called ''the drug-law industrial complex'' in the United States.

''I don't believe anyone should go to jail for using a psychoactive
substance,'' Morgan told the committee.

The committee's hearings continue.