Does Pennsylvania's Medical Marijuana Act only protect status and not use?

Why is it so hard to write a clear and easy-to-understand statute? Pennsylvania has a fairly new Medical Marijuana Act (MMA). The statute protects "an individual who is certified to use medical marijuana."

I have heard, however, some conjecture that employers may still maintain zero tolerance policies and terminate employees (or rescind offers to applicants) based solely on a positive (for marijuana) drug test - even if the employee is an MMA cardholder. The gist of the argument is that the statute protects the employee's status as a MMA cardholder, but not their use of marijuana. Under the language of the statute, there's certainly some room for that argument:

(1) No employer may discharge, threaten, refuse to hire or otherwise discriminate or retaliate against an employee regarding an employee's compensation, terms, conditions, location or privileges solely on the basis of such employee's status as an individual who is certified to use medical marijuana. 35 P.S. §  10231.2103(b)(1).

Emphasis on "solely" and status." But, that is tough to square with the next subsection of the statute:

(2) Nothing in this act shall require an employer to make any accommodation of the use of medical marijuana on the property or premises of any place of employment. This act shall in no way limit an employer's ability to discipline an employee for being under the influence of medical marijuana in the workplace or for working while under the influence of medical marijuana when the employee's conduct falls below the standard of care normally accepted for that position. 35 P.S. §  10231.2103(b)(2).

Why would the legislature create these carve-outs - focusing on workplace use and impairment - if all use could be banned? It would render subsection (2) meaningless surplus, which we try to avoid in statutory construction.

I'm not aware of any Pennsylvania courts weighing in on this issue. But, a Connecticut federal court ruled on precisely this argument (under a very similar Connecticut medical marijuana law). Pardon the lengthy bloc quote, but it's right on point:

Defendant next argues that PUMA prohibits discrimination only on the basis of one's status as an approved medical marijuana patient but not on account of one's use of medical marijuana in accordance with a PUMA program. For this argument, defendant relies on the language of the statute that forbids an employer from refusing to hire someone "solely on the basis of such person's or employee's status as a qualifying patient." Conn. Gen. Stat. § 21a-408p(b)(3). But the language and purpose of the statute make clear that it protects employees from discrimination based on their use of medical marijuana pursuant to their qualifying status under PUMA. Under defendant's restrictive interpretation of the statute, employers would be free to fire status-qualifying patients based on their actual use of medical marijuana—the very purpose for which a patient has sought and obtained a qualifying status. That makes no sense and would render the statute's protection against PUMA-based discrimination a nullity, because there would be no reason for a patient to seek PUMA status if not to use medical marijuana as permitted under PUMA.  

Moreover, the statute provides that "[n]othing in this subdivision shall restrict an employer's ability to prohibit the use of intoxicating substances during work hours or restrict an employer's ability to discipline an employee for being under the influence of intoxicating substances during work hours." Ibid. By negative implication, this language makes clear that PUMA protects a qualifying patient for the use of medical marijuana outside working hours and in the absence of any influence during working hours.

Noffsinger v. SSC Niantic Op. Co., LLC, No. 3:16-cv-01938 (D. Conn., Sept. 5, 2018).

To be clear, in my humble opinion, this issue is not resolved under Pennsylvania law, but employers should tread carefully.